315    MEM 


HANDBOOKS^ 


REESE  LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA 

Deceived 
^Accession  No. 


Class  i\<:> 


A  PRACTICAL  HANDBOOK 

ON  THE 

CARE  AND  MANAGEMENT 

OF 

GAS  ENGINES 

BY 

G.  LIECKFELD,  C.E. 


AUTHORIZED  TRANSLATION 

BY  G.  RICHMOND,  M.E. 
WITH  INSTRUCTIONS  FOR  RUNNING  OIL  ENGINES 


UNIVERSITY 

CAUFOR^i 


NEW  YORK : 

SPON  &  CHAMBERLAIN,  12  CORTLANDT  STREET 

LONDON : 

E.  &  F.  N.  SPON,  125  STRAND 
1896 


Entered,  according  to  Law,  with  the  Librarian  of  Congress, 
Washington,  D.  C., 

BY  SPON  &  CHAMBERLAIN,  1896. 


Burr  Printing  House,  18  Jacob  Street,  New  York,  U.S.A. 


NOTE  BY  TRANSLATOR. 


Believing  that  the  practical  instructions 
contained  in  Herr  Lieckf eld's  little  book 
would  prove  useful  to  users  of  gas  engines, 
permission  was  obtained  of  the  author  to 
translate  it.  The  fact  that  some  of  the  mat- 
ter relates  to  gas  engines  of  obsolete  form  is 
not  altogether  a  disadvantage,  since  it  may 
enable  the  owners  of  such  engines  to  prolong 
their  useful  life. 

At  the  request  of  the  publishers  a  chapter 
on  Oil  Engines  has  been  added.  In  the  limits 
allowed,  it  has  only  been  possible  to  refer  to 
the  "  Otto  "  Gas  Engine  and  the  "  Hornsby- 
Akroyd  "  Oil  Engine,  They  are  sufficiently 
representative,  however,  to  fairly  cover  the 
field. 


CONTENTS. 


CHAPTER  I. 

CHOOSING   AND   INSTALLING  A   GAS   ENGINE. 

PAGE 

THE  CONSTRUCTION  OF  GOOD  GAS  ENGINES 2 

External  appearance — Moving  parts — Oiling 
apparatus— Cylinder — Horizontal  and  vertical 
styles — Piston  and  valves — Governing  mech- 
anism. 

EXAMINATION  AS  TO  WORKMANSHIP 5 

Signs  of  good  work — Fit  of  bolts  and  nuts — 
Fit  of  links — Hardness  of  parts. 

EXAMINATION  AS  TO  RUNNING 7 

Starting  the  motor — Noiseless  running— The 
fly-wheel — The  governor. 

EXAMINATION  AS  TO  ECONOMY. 8 

To  ascertain  gas  consumption  when  running 
empty — Influence  on  consumption  of  gas  of 
different  methods  of  regulating — Proportion 
between  gas  consumption  at  full  load  and  one- 
quarter  load. 


vi  Contents. 

PAGE 

CONSIDERATION    AS   TO    RELIABILITY  AND    DURA- 
BILITY OF  GAS  ENGINES n 

The  power  of  engine  to  be  selected — Evil  effect 
of  continued  running  at  full  load — Influence 
on  the  durability  of  the  engine  of  the  means 
of  the  regulating. 

COST  OF  INSTALLING  A  GAS  ENGINE 13 

Amount  of  capital  needed — Running  expenses. 

PROPER  ERECTING  OF  GAS  ENGINES 16 

Selection  of  locality— Consideration  as  to  man- 
agement— As  to  neighborhood. 

CONSTRUCTION  OF  THE  FOUNDATION 17 

Foundation  drawings — Sandstone — Brick  and 
wood-work  foundation — Admissible  size  of 
engine  for  wood-work  foundation  in  dwelling- 
houses — Erecting  in  sub-cellared  basements. 

ARRANGEMENTS  FOR  GAS  PIPES 19 

Miscellaneous — Flickering  of  neighboring  gas 
flames — Gas  pressure  regulator — Water  drain 
cock  in  gas  pipes. 

RUBBER  BAG 20 

Setting  to  work — Protecting  same. 

COOLING  DEVICES 21 

Utilizing  existing  water  pipes — Coolers — Coil 
coolers — Expansion  vessel  of  coil  coolers — 
Superiority  of  coil  coolers  to  cooling  tanks 


Contents.  vii 

PAGE 

EXHAUST  PIPES 23 

Counter  pressure  in  long  or  narrow  conduit 
pipes — Inadmissibility  of  thin  tubes  or  brick 
chimneys  to  pass  off  exhaust  gases — Obstruc- 
tions in  exhaust  pipes — Corrosion  of  exhaust 
pipes— Removal  of  the  noise  of  exhaust. 

AIR  PIPES 25 

Material  of  air  pipes — Cleaning  the  air  and  gas 
pipes. 

SETTING  UP  GAS  ENGINES 26 

Cleaning  before  putting  together — Tightening 
the  foundation  bolts  and  nuts — Testing  be- 
fore the  first  start — Blowing  off  air  from  gas 
meter  and  gas  pipes. 

CHAPTER  II. 

BRAKES  AND  THEIR  USE  IN  ASCERTAINING  THE  POWER 
OF  GAS  ENGINES. 

THEORY  OF  THE  BRAKE 28 

The  Prony  brake — Making  a  Prony  brake — 
Means  of  obtaining  a  quiet  condition  of  the 
brake — How  to  ascertain  the  weight  of  the 
brake  lever  reduced  to  the  suspension-point — 
The  Prony  brake  with  vertical  lever — Means 
for  avoiding  the  oscillations. 

THE  BRAUER  BAND  BRAKE 36 

Parts  of  the  brake— Applying  the  brake  band- 
Mechanism  for  the  self-acting  maintenance  of 


viii  Contents. 

PAGE 

the  balanced  position — Length  of  lever  by 
calculation — Modified  suspension  of  weight — 
Precautions  for  the  use  of  the  brake — Seizing 
and  breaking  of  the  brake  band — Use  of  the 
brake  for  large  engines — Precautions  for 
loading  the  brake — Taking  off  the  load  and 
stopping  the  engine  after  finishing  the  test — 
Limit  of  heating  of  the  fly-wheel  rim — Rev- 
olution counter — Mechanism  for  convenient 
handling  of  the  revolution  counter — Manipu- 
lation of  the  revolution  counter — Ascertain- 
ing the  gas  consumption. 

ARRANGEMENT  OF  A  BRAKE  TEST 47 

Resistance  of  engine— Helpers  for  the  brake 
test  and  their  duties — Exact  determination  of 
the  duration  for  testing — Calculating  the 
power — Example  of  calculation — Defective 
handling  of  the  brake. 

EXPLANATION     OF     THE     EXPRESSION     "  BRAKE 
POWER"  AND  "INDICATED  POWER" 50 

COMPARISON  OF  THE  RESULTS  OF  THE  BRAKE  TEST 
AND  THE  INDICATED  TEST 50 

QUANTITY   OF    WORK    CONSUMED    BY    EXTERNAL 
FRICTION  OF  THE  ENGINE 51 

DISTRIBUTION  OF  HEAT  IN  A  GAS  ENGINE 51 

CHAPTER  III. 

ATTENDANCE  ON  GAS  ENGINES. 

GENERAL  REMARKS , 52 


Contents.  ix 

PAGE 

GAS  ENGINE  OIL 53 

Characteristic  qualities  of  the  oil — Composition 
— Comparison  of  different  oil  mixtures — Stir- 
ring around  the  oil  in  the  oil  tank — Indications 
of  good  and  bad  gas  engine  oil. 

CYLINDER  LUBRICATORS  55 

RULES    AS    TO   STARTING  AND    STOPPING   A   GAS 
ENGINE 56 

THE  CLEANING  OF  A  GAS  ENGINE 58 

Tools  to  remove  the  oil  coke— Precautionary 
measures  for  cleaning — To  loosen  tight  and 
burned  nuts — Examination  of  exhaust  pipe 
between  exhaust  valve  and  exhaust  pot — Test- 
ing the  engine  after  cleaning. 


CHAPTER  IV. 

GENERAL  OBSERVATIONS   AND   SPECIFIC  EXAMINA- 
TION FOR  DEFECTS 61 

Different  Kinds  of  Defects. 

i.  THE  ENGINE  REFUSES   TO  WORK  ON  ACCOUNT 

OF  LEAKY  EXHAUST  VALVE 63 

(a)  Because  the  valve  is  stuck  in  the  valve  bush- 
ing. Symptoms :  Explosions  in  the  ex- 
haust pipe  and  no  compression. 

(l>)  The    exhaust  valve    spring    is    too  weak. 
Symptoms  :  Vibration  of  the  valve. 


x  Contents. 

PAGE 

(c)  The  ground  valve  seat  surface  is  damaged. 

Symptoms  :  Vibration  of  the  valve,    explosion 

in  the  exhaust  pipe,  and  no  compression. 

2.  THE  ENGINE  REFUSES  TO  WORK   ON  ACCOUNT 

OF  THE   LEAKING   INLET  VALVE  ON    SLIDE 

VALVE 68 

Symptoms  :  No  compression  ;  gas  odor  above 
the  air  inlet  pipe  ;  yellowish-red  ignition 
flame. 

3.  NON-STARTING  OF  THE  ENGINE    ON    ACCOUNT 

OF  TIGHT  SETTING  OF  IGNITION  VALVE 69 

Symptoms  :  Noise  from  the  ignition  valve  ;  no 
compression  ;  suction  of  the  ignition  flame  ; 
explosion  and  gurgling  in  air-chamber. 

4.  NON-STARTING  OF  THE  ENGINE  ON  ACCOUNT  OF 

TOO  MUCH  PRESSURE  ON  THE  GAS 69 

Symptoms  :  Black  smoke  coming  out  of  the 
exhaust  pipe  ;  the  gas  bag  is  filled  up  tight  ; 
ignition  flame  is  burning  high  ;  ignition  flame 
yellowish-red. 

5.  STOPPAGE  BY  REASON  OF  DERANGEMENT  OF  THE 

GAS  METER 71 

6.  NON-STARTING  OF  THE  ENGINE  ON  ACCOUNT  OF 

TOO  MUCH  WATER  IN  THE  EXHAUST  POT.  . .     72 
Symptoms  :  Water  splashing  out  of  slide  valve, 
ignition  valve  and  exhaust  pipe  ;  the  cylinder 
is  sprinkled  with  water. 


Contents.  xi 

PAGE 

7.  STARTING  OF   THE    ENGINE    RENDERED    MORE 

DIFFICULT  ON  ACCOUNT  OF  LEAKY  PISTON.  .     73 
Symptoms :     Weak    compression ;    gas     odor 
around  the  piston  ;  oil  bubbles  around  the  end 
of  the  piston. 

8.  STARTING    THE    ENGINE    DIFFICULT    ON    AC- 

COUNT OF  CLOGGED  SLIDING  VALVE 75 

Symptoms  :  Crackling  noise  of  burning  oil  in 
sliding  valve. 

9.  STARTING   THE  ENGINE   RENDERED  DIFFICULT 

ON  ACCOUNT  OF  LEAKS  IN  GAS  PIPE 75 

Symptoms  :  Bad  lighting  of  the  ignition  flame, 
and  ignition  not  taking  place. 

10.  UNEXPECTED    STOPPING    OF    ENGINE    ON    AC- 

COUNT   OF   EXTINGUISHED,    FLICKERING,   OR 
EVEN  BURNING  OF  IGNITION  FLAME 77 

11.  IRREGULAR    RUNNING    ON    ACCOUNT    OF    EX- 

PLOSIONS NOT  TAKING  PLACE 78 

Symptoms  :  Heavy  knock  and  whistling  noise 
at  moment  of  ignition. 

12.  IRREGULAR    RUNNING    ON    ACCOUNT    OF    DE- 

FECTIVE GOVERNOR 79 

Symptoms  :    The  periods  of   moving  the  gov- 
ernor are  longer  than  in  normal  condition. 

13    Loss  OF  POWER  ON  ACCOUNT  OF  LEAKY  PIS- 
TON       80 

Symptoms  :  More  than  ordinary  odor    of  gas 


xii  Contents. 

PAGE 

and    burnt  oil  ;  misty  air    in  engine-room  ; 
increase  of  gas  bill. 

14.  Loss  OF  POWER   ON   ACCOUNT  OF  FORMATION 

OF  WEAK  GAS  MIXTURES. 81 

Symptoms  :  Crackling  noise  in  exhaust ;  gur- 
gling and  dull  crackling  in  air  inlet. 

15.  Loss  OF    POWER  ON   ACCOUNT   OF   REDUCING 

THE  QUANTITY  OF  MIXTURES. 82 

Symptoms  :  Dull  exhaust. 

16.  Loss  OF  -  POWER    ON  ACCOUNT    OF   RETAINED 

COMBUSTION  PRODUCTS 82 

Symptoms  :  Inside  wall  of  cylinder  being  dry  ; 
smoking  piston  ;  dull  dragging  noise  in  ex- 
haust. 

17.  Loss    OF  POWER  ON  ACCOUNT   OF  THE  LATE 

IGNITION 83 

Symptoms  :  Heavy  exhaust  ;  knocks  in  motor. 

1 8.  LOUD   REPORTS  IN  THE  EXHAUST  POT   (BACK 

FIRING) 84 

19.  KNOCKING  AND  THUMPING  INSIDE  OF  ENGINE..     84 

CHAPTER  V. 

DANGERS  AND  PRECAUTIONARY  MEASURES  IN  HANDLING 
GAS  ENGINES. 

EXAMINATION  OF  GAS  PIPES 86 

PRECAUTIONS  WHEN  OPENING  VALVES  AND  REMOV- 
ING PISTON  FROM  CYLINDER 87 


Contents.  xiii 

PAGE 

PRECAUTIONS    WHILE    EXAMINING    WITH     LIGHT 
OPENINGS  OF  GAS  ENGINES 89 

DANGERS  IN  STARTING :     89 

DANGER    IN    CLEANING     MACHINE    PARTS    WHEN 
RUNNING 89 

DANGERS     IN     TIGHTENING     BOLTS     AND      NUTS 
WHILE  RUNNING 90 

DANGER  IN    TOUCHING  WORKING  PISTON  OR  CON- 
NECTING RODS 90 

SAFEGUARD  FOR  THE  FLY-WHEELS 90 

DANGER    OF  PUTTING  ON   DRIVING   BELTS  WHILE 
RUNNING 90 

CHAPTER  VI. 

OIL  ENGINES. 

GAS  ENGINES  WITH  PRODUCER  GAS 91 

Gas-making  apparatus— Producer  g^s — More 
gas  used — Less  diluted — Can  be  used  in  same 
cylinder  as  ordinary  gas — Electric  ignition 
preferable. 

GASOLINE  AND  OIL  ENGINES 92 

Gas  produced  from  gasoline  by  carbureting  air — 
Distinction  between  gasoline  and  oil  engines. 

THE  "  HORNSBY  AKROYD"  OIL  ENGINE 93 

Simplicity  of  operation — Absence  of  ignition 
apparatus — Combustion — Mode  of  operation — 


xiv  Contents. 

PAGE 

Heating     of    vaporizer — Regulation — Direc- 
tions for  starting— Remarks. 

FAILURE  TO  START 99 

Vaporizer  not  hot  enough. 

EXAMINATION  OF  ENGINE  IN  DETAIL 100 

Oil  pump — Filter — Air  in  pipes— Suction  valves 
not  tight — Washing  out — Note  as  to  pump. 

VAPORIZER  VALVE  Box 102 

Construction— Operation — Examination— Test- 
ing correct  action. 

CONCLUDING  REMARKS 103 


CHAPTER  I. 

ON  THE  CHOICE  AND    PROPER  SETTING   UP 
OF  GAS   MOTORS. 

A  GOOD  gas  motor  should  be  of  simple 
construction,  with  all  its  working  parts 
well  in  view,  its  operation  easily  under- 
stood by  any  one,  and  its  running  quite 
regular  and  free  from  faults.  In  operation 
the  motor  should  not  make  a  disturbing 
noise  or  vibrate,  nor  should  any  irregular- 
ity in  running  strike  the  eyes  or  ears. 

The  consumption  of  gas  and  lubricating 
oil  should  not  be  greater  than  that  proper 
for  this  class  of  motors. 

The  cleaning  and  keeping  in  order 
should  be  easily  and  quickly  done. 

These  are  in  general  the  points  to  be 
kept  in  view  in  judging  a  gas  motor. 

Entering  a  little  more  into  detail  as  re- 


2  Setting  up  of  Gas  Motors. 

gards  the  construction,  it  may  be  said  that 
the  outside  appearance  of  the  machine 
should  give  the  impression  of  solidity  and 
strength. 

The  frame  should  have  a  broad  base. 
The  moving  parts  should  be  as  few  as  pos- 
sible, and  the  special  use  of  each  particu- 
lar motion  immediately  apparent.  The 
crank  shaft  and  connecting-rod  bearings 
should  be  adjustable.  For  oiling  the  pis- 
ton and  slide  valve  mechanically  operated 
oilers  are  preferable  ;  they  are  driven  by 
the  motor  itself,  and  the  oiling  is  effected 
independently  of  the  attendant.  So-called 
Oil  Drips  (self-feeders),  in  which  the  oil  is 
not  mechanically  supplied,  must  be  turned 
on  and  off  ;  besides,  they  do  not  oil  uni- 
formly, since  the  number  of  oil  drops 
diminish  as  the  level  of  the  oil  falls  ;  more- 
over, such  an  apparatus  easily  becomes 
stopped  up. 

The  working  cylinder  should  be  as  inde- 
pendent as  possible  of  the  frame  and  re- 
movable therefrom. 


Setting  up  of  Gas  Motors.  3 

In    horizontal    machines    those    having 
guide-bar  and  crosshead  (Fig.  i)  are  to  be 


FIG.  i. 

preferred  to  those  in  which  the  connect- 
ing-rod is  coupled  directly  on  to  the  piston 

(Fig.   2). 


FIG.  2. 

Where  the  room  for  setting  up  is  limit- 
ed,  requiring   contraction   of  the   motor, 


4  Setting  up  of  Gas  Motors. 

then  the  horizontal  type  without  special 
guide  or  the  vertical  type  should  be  chosen. 
In  either  case  it  is  well  to  secure  a  long 
and  light  piston.  Pistons  and  valves  should 
be  removable  in  the  shortest  possible  time, 
and  without  difficulty  ;  valve  and  cylinder 
covers  should  make  ground  joints — i.e., 
without  a  layer  of  packing  material  be- 
tween the  surfaces. 

It  is  preferable,  on  examining  a  motor, 
to  have  the  piston  and  discharge  valve 
taken  out  and  put  back.  These  operations 
ought  for  a  motor  of  not  more  than  4  Horse 
Power  to  be  easily  performed  by  one  man 
in  not  longer  than  ten  minutes. 

The  governing  mechanism  should  be 
well  in  sight  and  constructed  with  the  least 
possible  number  of  links.  The  pins  should 
be  long  and  fitted  in  bushes.  The  hard 
work  to  which  the  parts  of  a  gas  motor  are 
exposed  demands  that  the  greatest  care  be 
exercised  in  the  fitting  and  that  perfect 
material  be  employed. 

The  most  ingenious  and  excellent  con- 


Setting  up  of  Gas  Motors.  5 

structions  are  worthless  when  they  are  not 
well  put  together  and  perfect  in  running. 

The  well-known  motto  of  a  distinguished 
manufacturer,  "  Good  work  is  my  best 
patent/'  holds  for  no  machine  more  than 
for  the  gas  motor,  nor  are  the  machines  of 
the  latest  patent  necessarily  the  best. 
Caution  and  care  must  also  be  used  in 
the  examination  of  the  working  of  a  gas 
motor. 

Whoever  has  confidence  in  his  ability  to 
distinguish  good  from  bad  work  will  not 
neglect  to  dismount  each  part  of  the  motor 
with  his  own  hand  and  put  it  back  again 
in  its  place.  The  conclusions  as  to  work- 
manship which  are  reached  by  this  pro- 
ceeding are  often  startling. 

Even  for  the  less  experienced  there  are 
certain  marks  of  good  work  which  are  not 
to  be  mistaken,  and  their  presence  may 
be  accepted  as  an  indication  that  in  the 
rest  of  the  fitting  up  the  necessary  care 
has  been  bestowed.  To  these  indications 
belong,  before  all  things,  clean-cut  threads 


6  Setting  up  of  Gas  Motors. 

of  bolts  and  well-fitting  nuts — that  is,  the 
nuts  should  neither  be  too  loose  nor  too 
tight,  but  must  be  turned  by  the  hand 
without  effort  ;  also  the  spanners  supplied 
should  fit  exactly  on  the  nuts. 

Further,  all  the  linkages  should  be 
worked  to  a  sliding  fit  ;  when  a  movement 
is  given  by  the  hand  to  the  shanks  a  uni- 
form and  smooth  sliding  movement  should 
be  remarked.  Every  link  pin  should  be 
removable  from  its  place  by  a  blow  with 
the  hand,  although  it  must  be  a  close  fit  in 
the  hole  to  which  it  belongs. 

All  pins,  bushes,  cam  rollers,  slides,  and 
particularly  all  parts  which  are  subject  to 
wear  (where  hardening  is  not  impossible) 
must  be  glass  hard  to  the  depth  of  2  mm. 

One  can  test  with  a  file  the  hardness, 
and  from  fractured  parts  the  depth  of  the 
hardening  is  determined.  Makers  who 
pay  particular  attention  to  hardening  are 
worthy  of  confidence. 

Next  the  mode  of  starting  the  motor 
should  be  examined.  The"  starting"  han- 


Setting  up  of  Gas  Motors.  J 

die  should  be  pointed  out,  and  when  the 
motor  is  of  less  than  6  Horse  Power  an  at- 
tempt should  be  made  to  start  it  without 
help.  Without  too  great  an  exercise  of 
strength  the  forward  running  should  be  set 
up  after  three  or  four  revolutions  of  the 
fly-wheel. 

When  the  motor  has  reached  its  normal 
number  of  revolutions,  then  its  working  is 
to  be  observed,  and  no  trace  of  thumping 
or  pounding  at  the  moment  of  ignition 
should  be  heard  or  felt,  when  the  hand  is 
placed  on  any  part  whatever  of  the  cylin- 
der or  framework. 

The  fly-wheel  should  run  perfectly  true 
if  the  finger  is  placed  on  the  outer  side  of 
the  revolving  fly-wheel  so  as  to  scrape  the 
nail,  then  neither  trembling  nor  unsteadi- 
ness of  the  periphery  should  be  felt  at  the 
moment  of  ignition  ;  such,  if  present, 
would  be  due  to  defective  fitting  or  too 
small  crank  shaft. 

All  levers,  rollers,  and  slide  rods  in  con- 
nection with  the  governing  should  work 


8  Setting  up  of  Gas  Motors. 

smoothly  ;  they  should  not  snap  or  be 
forced  out  of  their  proper  path. 

The  less  noise  the  cog  wheels  make  the 
more  noiseless  the  valves,  cams,  and  levers 
of  the  regulating  gear  work,  the  less  the 
machine  hisses  and  puffs,  the  less  the  neigh- 
borhood of  the  motor  smells  of  gas  and 
burned  oil,  so  much  the  better  is  the  mo- 
tor constructed  and  run,  and  so  much 
more  agreeable  will  it  be  to  have  to  do 
with  it. 

When  an  opinion  has  thus  been  lormed 
as  to  the  solidity  of  construction  and  the 
ease  of  running  there  remains  the  question 
of  economy — that  is,  the  gas  required  by 
the  motor. 

For  this  purpose  let  the  belt  be  thrown 
off  and  observe  the  throwing  in  and  out  of 
gear  of  the  controlling  mechanism  while 
the  motor  runs  empty. 

Nowadays  it  is  to  be  expected  that  in 
such  case  for  one  power  stroke  six  omis- 
sions will  occur,  and  thereof  the  gas  con- 
sumption for  no  load  should  not  be  more 


Setting  up  of  Gas  Motors.  9 

than     i -/th     of     that     required    for    full 
power.* 

The  number  of  revolutions,  'first  for  no 
load,  then  for  full  load  for  the  same  period 
of  time,  about  5  minutes,  should  be  taken. 
With  no  load  the  machine  runs  faster  than 
when  loaded  ;  the  difference  between  the 
total  revolutions  should  not  be  more  than 
5  per  cent.  The  loading  of  the  motor  can 
be  done  by  pressing  a  wooden  beam  against 
the  fly-wheel,  the  full  load  in  which  no 
misfires  occur  should  not  be  reached  by 
these  means. 


*  It  is  here  understood  the  regulation  of  speed  is  by  periodic 
full  power.  There  are  other  methods  by  which  the  regulation 
under  variable  load  is  effected,  but  for  no  load  these  are  not  so 
economical,  while  they  give  more  uniform  rate.  Now  read  of 
the  gas  consumption  observed  from  the  dial  of  the  gas  meter 
for  a  period  of  about  five  minutes. 

Good  gas  motors  should,  if  the  exhaust  pipe  is  not  too  long 
or  too  small,  consume  for  no  load  the  amounts  of  gas  in  the 
following  table  : 

Horse  Power,  }£,        i,       2,       4,       6,       8,        10. 

Cubic  feet  gas  per 
hour  without  load,    6,       9,      13,      25,      50,      67,        72. 

The  amount  of  gas  required  for  full  load  can  be  exactly  ob- 


io  Setting  up  of  Gas  Motors. 

In  general,  it  may  be  remarked  that  a 
guarantee  is  furnished  by  the  maker  as  to 
the  maximum  power  of  the  motor  and  as 
to  the  consumption  of  gas  per  hour  per 
full,  1-2,  and  1-4  load.  The  consump- 
tion of  gas  'per  hour  and  Horse  Power 
for  1-4  load  at  the  highest  may  be  double 
as  great  as  for  full  power.  The  less  the 
gas  consumption  for  no  load  is,  so  much 
more  economically  the  motor  works  in 
use,  when,  as  is  generally  the  case  in  small 
businesses,  the  power  requirement  is  very 
variable. 

A  great  number  of  reserve  pieces  for 
this  or  that  part  of  the  motor  is  no  recom- 
mendation for  it ;  just  as  little  is  a  number 
of  special  tools  for  taking  it  apart  and 
cleaning.  Moreover  instructions  for  run- 
ning prolix,  and  difficult  to  understand,  do 


tained  only  by  the  help  of  the  power  brake,   respecting  the 
handling  of  which  the  next  chapter  will  treat. 

The  regularity  of  running  can  be  approximately  judged  of 
by  listening ;  more  correct  conclusions  can  be  attained  by 
counting  the  revolutions  by  the  watch. 


Setting  up  of  Gas  Motors.  n 

not  argue  well  for  an  engine  ;  it  is  well 
to  ask  for  the  instruction  book  before  de- 
ciding on  the  purchase. 

Nor  should  the  cost  of  a  journey  deter 
from  watching  the  performance  of  motors 
of  different  systems  for  a  length  of  time, 
in  order  to  learn  the  opinions  of  owners 
and  drivers  and  personally  determine  the 
merits  of  the  motors. 

Only  those  motors  which  for  years  have 
performed  hard  duty  without  derangement 
in  running  secure  a  recommendation  for 
their  makers. 

It  cannot  be  too  often  asserted  that  dura- 
bility and  certainty  of  running  count  be- 
fore everything,  since  these  are  the  only 
grounds  upon  which  certainty  of  continued 
undisturbed  service  of  the  machine  de- 
pend. Cheapness  and  oil  consumption  stand 
in  the  second  rank  only. 

With  regard  to  the  power  of  motor  to 
be  chosen  the  following  point  may  be 
noted  :  the  majority  of  dissatisfied  own- 
ers of  motors  will  be  found  to  complain  of 


12  Setting  up  of  Gas  Motors. 

leaking  pistons.  When  the  circumstances 
of  running  are  investigated  it  is  almost 
uniformly  found  that  a  motor  of  too  little 
power  has  been  chosen  and  the  same  has 
been  overworked. 

A  gas  motor  which  is  continually  worked 
with  full  load,  however  it  may  be  con- 
structed, is  overworked,  and  will  always 
be  ruined  in  a  comparatively  short  period. 
The  cylinder  and  piston  of  gas  motors 
should  be  cooled  not  only  by  water  in  the 
jacket,  but,  especially  in  large  motors,  by 
interior  cooling  and  cool  air.  This  cooling 
follows  naturally  in  motors  in  which  the 
regulation  is  by  periodic  full  charge,  when 
the  cut  off  of  the  gas  occurs  in  regular  suc- 
cession, and  air  only  is  drawn  in  which  is 
in  direct  contact  with  the  cylinder  walls 
and  piston  end. 

In  running  at  full  load  cut  offs  should 
occur,  and  therefore  intelligent  manufac- 
turers give  their  motors  such  dimensions 
that  when  running  continually  with  full 
load,  with  no  cut  off,  develop  20  to  25  per 


Setting  up  of  Gas  Motors.  13 

cent,  more  power  than  that  at  which  they 
are  rated  in  the  price-lists. 

From  these  considerations  it  follows, 
further,  that  for  those  motors  which  regu- 
late by  periodic  full  charge  a  longer  life  is 
to  be  prophesied  under  similar  conditions 
than  for  those  which  work  with  variable 
charge. 

Whoever  has  had  occasion  to  discuss 
gas  engines  with  professional  dealers  will 
have  remarked  that  they  gave  the  impres- 
sion that  the  cost  of  an  installation  in  run- 
ning order  is  limited  to  the  purchase  price 
of  the  motor.  The  necessary  expenditure, 
however,  is  often  very  considerably  great- 
er than  this. 

The  following  items  in  the  cost  of  such 
an  installation  must  be  noted  : 

(a)  CAPITAL  INVESTED. 

(1)  Purchase  price  of  the  motor. 

(2)  Freight  and  cartage. 

(3)  Setting  up  of  foundation  and  special 
building  work. 


14  Setting  up  of  Gas  Motors. 

(4)  Cost  of  erecting  piping   (gas   pipes 
with   gas  regulator,    water  pipe,   exhaust 
piping  and  overflow  for  cooling  water). 

(5)  In  the  case  where  a  water  supply  is 
not  at  the  user's  disposal  the  cost  of  pro- 
viding a  cooling  vessel  or  any  cooler  with 
the  suitable  piping. 

(6)  Cost  of  erection,  including  railway 
fare,  lodging,  boarding,  and  wages  for  the 
erector.     According   to    the   size    of    the 
motor,  the  time  of  fitting  up  may  be  taken 
approximately  as  follows  :  For  motors  up 
to  2  Horse  Power,  3  days  ;  up  to  6  Horse 
Power,  5  days  ;  up  to  15  Horse  Power,  10 
days. 

(b)  RUNNING  EXPENSES  IN  USE. 

(1)  Interest  on  the  capital  invested. 

(2)  Renewal  and  cost  of  repairs  for  the 
motor  10  per  cent,  and  for  the  other  part 
of  the  investment  5  per  cent. 

(3)  Rent. 

(4)  Cost  of  gas,  cooling  water,  lubricat- 
ing oil,  waste,  etc. 


Setting  up  of  Gas 

For  the  gas  consumption  we  may  reckon 
1.2  cubic  meter  (42  cubic  feet)  ;  for  small 
motor,  i  cubic  meter  (35  cubic  feet)  ;  for 
medium  size  and  for  the  larger  sizes,  8 
cubic  meters  (28  cubic  feet).* 

Cooling  water  consumption  by  Horse 
Power  and  per  hour  for  small  motors, 
40  /.  (9  galls.)  ;  medium,  35  /.  (8  galls.), 
and  larger,  30  /.  (7  galls.). 

The  oil  consumption  varies  very  much 
according  to  the  construction  of  the  motor, 
whether  vertical  or  horizontal,  and  with 
or  without  a  crosshead. 

Data  regarding  this  will  be  obtained 
from  the  maker  furnishing  the  machine. 

(5)  Cost  of  attendance  and  cleaning  of 
the  motors  are  approximately  taken  as  one 
hour's  wages  per  day. 

Let  us  pass  to  the  question  of  the  special 
provisions  for  the  installation. 

Of  first  importance  is  the  choice  of  the 


*  These  quantities  have  been  considerably  reduced  in  the 
better  class  of  modern  gas  engines.    (Translator,) 


1 6  Setting  up  of  Gas  Motors. 

location  itself,  which  must  be  carefully 
considered. 

When  practicable  the  motor  should  be 
placed  in  a  separate  room.  In  carpenters' 
shops,  saw  mills,  tobacco  factories,  foun- 
dries, and  especially  in  all  trades  where 
flying  dust  is  inevitable,  the  motor  should 
have  a  separate  room  ;  if  this  cannot  be 
provided,  a  room  should  be  boarded  off 
and  provided  with  windows. 

This  motor  room  should  be  well  lighted 
and  roomy,  so  that  easy  access  can  be  had 
to  the  motor  on  all  sides  and  on  the  side 
of  the  fly-wheel,  where  the  workman  has 
to  go  to  start  the  engine,  at  least  3  feet 
space  should  be  left. 

Arrange  the  setting  of  the  motor  for 
direct  driving  (a  crossed  belt  is  to  be 
avoided).  The  gas  and  exhaust  piping 
should  be  as  short  and  direct  as  possible. 
Neighbors  of  gas  motors  raise  great  objec- 
tions to  the  smell  and  noise  of  the  exhaust, 
and  care  should  be  taken  that  cause  for 
such  complaints  shall  be  avoided.  Very 


Setting  up  of  Gas  Motors.  17 

often  the  first  feeling  of  satisfaction  which 
the  owner  of  a  well-running  machine  ex- 
periences is  very  properly  upset  by  the 
complaints  of  angry  neighbors. 

These  preliminaries  attended  to,  and  the 
ground  plan  showing  the  requisite  piping 
supplied,  we  may  proceed  with  the  prepa- 
ration of  the  foundation,  and  finally  with 
the  erection  of  all  the  piping  up  to  the 
connections  with  the  motor. 

The  drawings  of  the  foundation  are  fur- 
nished by  the  maker  of  the  motor,  from 
whom  also  may  be  obtained  the  dimensions 
ot  the  different  pipes,  thickness  and  width 
of  the  driving  pulley,  direction  of  running, 
and  many  other  obvious  points. 

If  the  motor  is  to  be  placed  on  the 
ground  the  foundation  pit  must  be  dug 
out  to  the  solid  earth.  This  must  be  taken 
account  of  in  estimating  the  cost  of  ma- 
sonry. 

For  small  foundations — say  for  motors 
up  to  2  Horse  Power— often  a  single  sand- 
stone slab  will  answer. 


1 8  Setting  up  of  Gas  Motors. 

As  material  for  brick  foundations,  hard- 
burned  bricks,  well-binding  Portland  ce- 
ment, and  clean,  sharp  building  sand  are 
to  be  employed.  Sufficient  time  must  be 
allowed  for  the  cement  to  harden. 

It  is  well  known  that  cement  is  weak- 
ened by  continued  action  of  oil.  Motors 
should  be  provided  with  so-called  oil  curb 
to  prevent  the  overflowing  of  the  lubricat- 
ing oil.  As  it  is,  nevertheless,  impossible 
to  prevent  oil  from  time  to  time  getting 
on  the  masonry,  it  is  usual  to  replace  the 
upper  four  or  five  courses  of  brick  with  a 
block  of  sandstone. 

For  setting  motors  on  joists  of  floors  in 
old  houses,  full  assurance  should  be  had 
as  to  the  good  condition  and  sufficient 
strength  of  the  beams.  In  any  case  the 
floor  boards  should  be  taken  up  in  the 
neighborhood,  so  that  all  the  joists  may  be 
inspected.  Tf  these  precautions  are  not 
taken  there  is  danger,  sooner  or  later,  of 
breaking  down  the  floor. 

To  avoid   springing  of   the  joists,    the 


Setting  up  of  Gas  Motors.  19 

motor  is  preferably  to  be  placed  in  a 
corner. 

Motors  ol  the  vertical  style  above  4 
Horse  Power  should  not  be  placed  on  the 
upper  floor  of  ordinary  dwelling  houses 
unless  the  joists  and  the  supporting  brick- 
work are  strengthened. 

Cellar  vaults  or  the  concrete  flooring  of 
modern  houses  should  not  be  utilized  for 
the  direct  installation  of  gas  motors  ;  in 
such  cases  it  is  better  that  the  foundation 
should  be  built  from  the  cellar  floor  up  to 
the  level  of  the  vault  with  special  pillars 
of  sufficient  strength. 

To  place  the  gas  piping,  the  following 
hints  will  be  useful  : 

Above  all,  choose  pipes  of  sufficient  size, 
and  sharp  bends  should  be  avoided  as  far 
as  possible. 

Where  the  neighborhood  would  be  an- 
noyed by  the  flickering  of  the  gas  or  where 
changes  in  gas  pressure  are  to  be  expected 
a  pressure  regulator  should  unquestionably 
be  installed. 


2o  Setting  up  of  Gas  Motors. 

Leading  the  gas  pipe  through  rooms  of 
different  temperatures  is  to  be  avoided  as 
far  as  possible.  At  the  lowest  point  of  the 
gas  piping,  in  close  proximity  to  the  motor, 
a  J-inch  blow-off  cock  and  drain  pipe 
should  be  placed  to  serve  for  carrying  off 
the  water  collected  in  the  pipe  ;  it  also 
serves  the  purpose  of  blowing  off  the  gas 
when,  after  long  standing  of  the  motor,  it 
is  diluted  with  air  ;  it  serves  also  when  it 
is  desired  to  measure  the  gas  pressure  or 
maintain  an  open  flame  close  at  hand. 

The  rubber  bag  serves  its  purpose  better 
•the  nearer  it  is  to  the  motor.  The  pulsat- 
ing motion  of  the  bag  endangers  its  pull- 
ing off  from  the  pipe.  As  this  may  cause 
a  dangerous  escape  of  gas,  care  should  be 
taken  to  secure  the  mouth  of  the  bag  to 
the  pipe  by  winding  wire  around  it. 

Oil  destroys  rubber  and  changes  it  into 
a  sticky,  viscous  mass  ;  hence  the  rubber 
bag  must  be  placed  out  of  reach  of  the  oil 
splashing  from  the  connecting-rod  and 
governor  or  protected  with  a  cover. 


Setting  up  of  Gas  Motors.  21 

In  laying  out  the  cooling  connections  it 
may  be  remarked  that  the  piping  for  con- 
veying the  water  (under  pressure)  must  be 
of  sufficient  capacity.  In  most  systems  of 
motors  the  water  must  enter  the  jacket  at 
the  bottom,  and  the  overflow  at  the  top 
should  pass  into  a  funnel,  so  that  it  can  be 
seen  and  be  tested  as  to  the  temperature 
of  the  water  at  any  time,  which  should  not 
be  above  70°  C.  (158°  Fahr.). 

Cooling  tanks,  unless  very  small,  should 
not  be  placed  in  the  same  room  with  the 
motor  ;  the  tank  is  better  placed  in  a  cool 
place  where  a  current  of  air  obtains.  The 
best  place  is  an  unused  Corner  of  the  house 
floor,  as  near  as  possible  to  the  motor.  The 
higher  the  cooling  tank  the  more  rapid 
the  circulation  of  the  water. 

The  pipe  which  connects  the  upper  part 
of  the  motor  jacket  with  the  upper  part  of 
the  tank  must,  in  all  cases,  be  fixed  with 
a  continually  rising  column.  For  air  cool- 
ers the  above  remark  is  even  more  impor- 
tant. The  lowest  point  of  the  cooler 


22  Setting  up  of  Gas  Motors. 

should  be  at  least  i  meter  (3  feet,  3  inches) 
above  the  lowest  point  of  exit  for  the 
water  from  the  jacket. 

For  driving  off  of  the  heated  air  from 
the  upper  end  of  the  cooler  and  also  the 
drawing  in  of  cold  air  to  the  barrel  the 
same  care  must  be  taken  to  provide  proper 
openings  in  the  sides  of  the  same. 

The  connecting  pipes  between  the  cooler 
and  the  motor  should  be  as  short  as  possi- 
ble. All  bends  must  be  in  the  form  of 
well-rounded  curves. 

As  the  water  contained  in  a  pipe  coil 
cooler  by  becoming  heated  is  expanded, 
place  for  the  surplus  must  be  provided 
for  with  a  so-called  expansion  vessel. 
This  expansion  vessel  placed  above  will  be 
provided  with  a  loose  cover,  and  is  prefer- 
ably connected  with  a  cooler  with  a  small 
pipe,  say  J  inch.  The  surplus  water  takes 
up  little  room  in  the  expansion  vessel,  and 
the  loss  by  evaporation  is  small,  so  that 
refilling  is  seldom  necessary. 

The  advantages  of  the  pipe  coil  over  the 


Setting  up  of  Gas  Motors.  23 

cooling  tank  lies  in  the  fact  that  on  the 
cooler  heating  up  a  permanent  condition 
is  soon  established  ;  it  requires  less  space, 
a  smaller  quantity  of  water  is  required  for 
filling  it,  and  it  may  be  used  with  advan- 
tages for  heating  and  ventilation  purposes. 

The  fitting  up  of  the  exhaust  pipe  often 
presents  difficulties  ;  the  products  of  com- 
bustion flow  through  this  pipe  with  a  high 
velocity,  great  length,  small  diameter, 
sharp  bends,  create  considerable  back 
pressure  on  the  piston  and  a  very  appreci- 
able loss  of  power. 

At  the  present  there  are  no  motors  in 
which  the  accidental  entrance  of  uncon- 
sumed  gas  into  the  exhaust  pipe  can  be 
counted  on  as  an  impossibility  ;  moreover, 
as  the  working  principle  of  the  gas  motor 
ensures  that  sooner  or  later  this  escaped 
gas  will  take  fire,  it  is  necessary  that  the 
walls  of  the  exhaust  pipe  should  be  strong 
enough  to  bear  a  pressure  of  5  to  6  atmos- 
pheres (60  to  75  Ibs.  per  square  inch).  Zinc 
pipes,  drain  pipe,  masonry  chimneys  or 


24  Setting  up  of  Gas  Motors. 

canals  are  once  for  all  excluded  from  use 
as  conducting  pipes  for  the  exhaust.  Only 
wrought  iron  or  cast  iron  of  sufficient 
thickness  should  be  chosen  ;  the  presence 
of  sharp  corners,  already  warned  against, 
may  not  only  diminish  the  work  performed, 
but  may  even  cause  stoppage  of  the  ma- 
chine. The  burned  products  drive  a  great 
part  of  the  lubricating  oil  in  pulverized 
form  through  the  pipes  into  the  open  air, 
where  this  oil  dust  strikes  against  the  hot 
bend  of  the  wall  of  the  pipe,  it  is  cooled, 
forming  the  well-known  oil  coke,  which 
gradually  becomes  a  perfect  wax,  and  in 
course  of  years  may  fill  the  whole  pipe 
aperture.  Mysterious  derangement  in  run- 
ning, with  falling  off  of  power,  great  gas 
consumption  knocking  in  the  exhaust  pot, 
often  have  their  cause  in  this  stopping  up 
of  the  exhaust  pipe.* 


*  For  a  certain  gas  motor,  in  spite  of  careful  attendance,  the 
gas  bill  advanced  in  the  course  of  a  year  from  23  M.  per  month 
to  58  M.,  without  any  increase  in  the  work  done.  All  endea- 
vors to  find  out  the  cause  of  the  trouble  were  fruitless.  At 


Setting  up  of  Gas  Motors.  25 

The  products  of  combustion,  and  espe- 
cially condensed  water  vapor,  cut  into  the 
material  of  the  exhaust  pipe.  The  oxidiza- 
tion goes  on  more  quickly  in  the  horizon- 
tal stretch  of  a  pipe,  and  such  a  disposition 
is  to  be  avoided. 

There  are  several  methods  of  preventing 
the  noise  of  the  exhaust — choking  the  ori- 
fice of  the  exhaust  pipe,  putting  in  circuit 
several  pots,  one  behind  the  other,  or  a 
battery  of  broken  stones.  By  one  or  other 
of  the  two  last  methods  the  noise  can  be 
entirely  suppressed.  In  all  cases,  how- 
ever, the  available  work  is  diminished  by 
this  procedure. 

Pipes  for  bringing  good  working  air 
often  become  necessary  ;  they  ought  not 
to  be  ot  zinc  or  tin,  since  return  fir- 
ing through  the  air  pipe  may  occur,  so 


length,  when  by  accident  the  exhaust  pipe  came  apart,  it  was 
found  that  instead  of  a  mouthpiece  of  2-inch  pipe  in  the  ex- 
haust pot,  it  was  so  stopped  up  that  the  little  finger  could  with 
difficulty  be  placed  in  the  hole. 

After  a  thorough  cleaning  of  the  pipe  the  gas  consumption 
went  back  to  the  usual  amount. 


26  Setting  up  of  Gas  Motors. 

that  here  also  wrought  iron  should  be 
used. 

The  air  pipes  and  the  part  of  the  gas 
pipe  which  makes  the  connection  between 
the  gas  bag  and  the  motor  should,  before 
fitting  up,  be  most  carefully  cleared  of 
scale,  iron  cuttings,  sand,  etc.,  by  tapping 
with  a  hammer  and  blowing  through  them. 

The  setting  up  of  the  motor  will  always 
be  best  done  by  an  employe  of  the  firm 
supplying  it  ;  well-grounded  complaints 
cannot  then  be  met  by  the  answer  that 
they  are  due  to  faults  in  connecting.  It  is 
only  necessary  in  this  place  to  say  with 
respect  to  the  erection  that  all  parts  of  the 
motor,  before  setting  it  to  work,  must  be 
taken  apart  and  cleaned  from  dust,  dirt, 
and  particles  of  packing  material. 

The  nuts  of  the  anchor  bolts  must  never 
be  tightened  up  before  the  complete  hard- 
ening of  the  layer  of  cement  filling  up  the 
space  between  the  base  plate  and  the  foun- 
dation ;  this  is  particularly  the  case  in  hori- 
zontal engines.  By  starting  prematurely 


Setting  up  of  Gas  Motors.  27 

the  engine  frame  may  be  sprung,  so  that 
after  running  a  short  time  a  heating  up  or 
even  seizing  of  the  crank  pin  may  occur. 
Before  leaving  it  the  motor  should  be  tried. 
The  tightness  of  all  valves  and  joints  must 
be  tested.  Before  finally  setting  the  motor 
to  work  the  air  must  be  blown  out  from 
the  meter  and  the  gas  pipe.  This  is  most 
easily  accomplished  by  turning  over  the 
motor  into  the  position  in  which  it  takes  in 
gas.  Then  open  the  gas  cock  and  wait  till 
a  strong  smell  of  gas  is  perceptible  in  the 
air  pipe. 

With  motors  having  a  self-acting  mixing 
valve  it  is  necessary  to  hold  this  open  dur- 
ing the  blowing  through.  Of  course  all 
open  flames  in  the  neighborhood  must  be 
put  out  and  the  windows  opened. 


CHAPTER    II. 

THE  DYNAMOMETER  AND  ITS  USE  IN  ASCER- 
TAINING THE  POWER  OF  GAS  MOTORS. 

THE  apparatus  which  is  most  generally 
used  as  a  means  of  determining  the  power 
of  a  motor  closely  resembles  the  brakes  of 
winches  and  hoists  of  all  kinds  ;  these  differ 
only  from  the  dynamometer  in  that  the 
fulcrum  of  the  latter  is  movable  within 
certain  limits,  so  that  by  regulating  the 
weight  a  pressure  can  be  applied  which 
the  fulcrum  would  have  if  it  were  immov- 
able. 

If  the  power  brake  is  fixed  on  the  pulley 
or  fly-wheel  of  a  motor,  then  by  tighten- 
ing up  little  by  little  on  the  same  as  much 
friction  work  is  imposed  on  the  motor  as 
it  is  able  to  overcome  and  for  any  desired 
period  of  time. 


Dynamometer,   Tests  for  Power.        29 

The  amount  of  friction  work,  and  hence 
the  power  of  the  motor,  is  determined  by 
the  velocity  with  which  the  friction  resist- 
ance is  overcome,  and  is  measured  by  the 
product  of  these  two  quantities. 


FIG.  3. 

The  simplest  and  oldest  of  the  power 
brakes  is  that  shown  in  Fig.  3,  "  The  Prony 
Brake." 

In  the  use  of  this  apparatus  the  brake 
blocks  a  are  tightened  up  until  the  motor  at 
full  power  moves  with  the  normal  number 
of  revolutions,  then  the  balance  weight 
Q  is  so  adjusted  that  the  lever  swings 


30        Dynamometer,    Tests  for  Power. 

permanently  between  the  stops  c  of  the 
standard  d. 

In  fitting  up  the  brake,  the  lightest  wood 
possible  is  to  be  chosen  ;  the  brake  blocks 
themselves  should  be  made  of  lime  or  pop- 
lar. They  should  have  on  the  rubbing 
surfaces  deep  and  wide  oil  grooves,  which 
must  be  filled  with  stiff  grease.  Wing 
nuts  serve  to  draw  up  the  blocks,  which 
should  have  as  long  wings  as  possible,  so 
that  they  can  be  turned  by  hand  with  ease 
and  certainty. 

The  brake  pulley  must  have  flanges,  by 
which  the  slipping  off  of  the  brake  at  the 
sides  is  prevented  ;  it  must  run  perfectly 
round  and  be  keyed  fast  to  the  motor. 

For  holding  the  weight  a  bag  of  stout 
canvas  may  be  used.  With  very  small 
motors  the  brake  weight  can  be  supplied 
by  a  spring  balance  hooked  between  the 
floor  and  the  lever.  If  the  brake  does  not 
remain  in  equilibrium,  but  makes  long  peri- 
odic vibrations  between  the  stops,  then  it 
is  a  good  plan  to  put  one  or  two  rubber 


Dynamometer,   Tests  for  Power.        3 1 

• 

washers  under  the  binding  nuts  of  the 
brake  blocks.  By  these  means  a  firmer 
grip  is  obtained  for  the  nuts,  and  the  ar- 
rangement is  fastened  up  with  security 
even  when  the  pulley  is  not  perfectly 
round,  or  the  brake  lever  springs. 

Besides  the  direct  loading  weight  Q  the 
resistance  on  the  fixed  point  is  increased 
by  the  weight  of  the  brake  itself ;  and  the 
weight  of  the  arm,  q,  must  be  added  to  the 
weight  Q. 

q  may  be  easily  estimated  by  calculation 
with  approximate  correctness  ;  this  weight 
can,  however,  be  obtained  quicker  and 
more  accurately  by  direct  weighing  in  the 
following  manner  : 

A  light  stick  is  bolted  between  the  brake 
blocks  and  a  round  iron  rod  inserted  in  the 
middle  of  the  same,  and  the  hook  of  the 
lever  is  placed  in  a  scale  and  weighed 
while  the  other  end  of  the  brake  is  sus- 
pended in  suitable  bearing  by  the  iron  rod 

(Fig-  4). 

The  weight  thus  obtained  indicates  the 


32        Dynamometer,   Tests  for  Power. 

reduction  of  weight  to  be  suspended  from 
the  hook — viz.,   q,   when   the   round   iron 


FIG.  4. 

fulcrum  is  so  placed  that  the  brake  lever 
occupies  the  position  it  will  have  when  in 
use. 

If   the  distance    from  the   vertical   line 

through    the    hook    to    the    vertical    line 

through  the  fly-wheel  center  is  /  feet,  while 

n  is  the  number  of  revolutions  per  min- 

ute, and  therefore 
nnl(7t  =  3.1416)  =  the   number  of  feet 

per  minute, 

Q  -f-  q  the  total  weight  hanging  on  the 
lever,  then  the  work  in  foot  pounds 
per  minute 


or  Horse  Power  =  W  ~  33000. 


Dynamometer,   Tests  for  Poiver.       33 

The  installation  of  a  hanging  beam  is 
often  inconvenient,  and  frequently  another 
arrangement  of  brake,  such  as  shown  in 
Fig.  5,  may  be  seen,  especially  in  gas  mo- 


tor factories  where  motors  of  small  power 
are  to  be  tested. 

The  brake  in  this  case  is  made  entirely 
of  wrought  iron.  As  the  lever  of  the  bal- 
ance is  vertical  and  the  whole  apparatus 
can  be  made  very  light,  its  weight  adds 
very  little  to  the  frictional  resistance  on  the 
pulley,  and  may  generally  be  neglected. 

The  bracket  F  serves  as  a  precaution 
against  overwinding  of  the  brake  by  form- 
ing a  stop  for  the  weight  K, 


34        Dynamometer,   Tests  for  Power. 

A  third  arrangement,  by  the  use  of 
which  the  stop  bracket  may  be  avoided,  is 
shown  in  Fig.  6. 

As  seen,  the  brake  lever  is  made  with 
two  arms  and  is  provided  with  a  stop,  5  /,  at 
each  end,  which  reaches  nearly  to  the  floor, 
in  order  to  steady  the  brake  lever.  Brakes 
constructed  in  this  manner  are  very  easy 


FIG.  6. 

to  handle,  and  in  most  cases  can  be  very 
easily  fixed.  In  working  with  them,  how- 
ever, there  is  one  inconvenience,  namely, 
that  it  is  very  difficult  to  obtain  a  perfect 
equilibrium. 

The  momentum  of  this  overhanging  ap- 
paratus, which  is  twice  as  heavy  as  that  of 
Fig.  3,  together  with  the  elasticity  of  the 


Dynamometer,   Tests  for  Power.        35. 

wood,  cause  a  pendulum  action  resulting 
in  alternate  striking  of  the  feet  against  the 
floor. 

Most  experimenters  are  satisfied  that 
when  this  pendulum  motion  occurs  the 
correct  balance  is  obtained  ;  this,  however, 
is  not  the  case  ;  on  the  contrary,  it  will  be 
found  that  with  a  stationary  balance  con- 
siderably smaller  brake  ..results  will  be  ob- 
tained. 

In  this  connection  the  before-mentioned 
rubber  washers  perform  important  service. 

Every  form  of  application  of  the  Prony 
brake  demands  the  provision  of  a  brake 
pulley  with  flanges,  whose  preparation  arid 
proper  fastening  to  the  motor  is  often  at- 
tended with  difficulties. 

As  every  motor  is  provided  with  a 
turned  and  perfectly  round  fly-wheel,  the 
idea  of  utilizing  it  as  a  brake  pulley  is  ob- 
vious. On  account  of  its  great  diameter 
and  the  narrow  width  of  the  rim  the  Prony 
brake  cannot  be  used  in  this  case,  and  the 
band  brake  must  be  applied. 


36        Dynamometer,   Tests  for  Power. 

The  first  band  brake  now  in  general  use 
was  constructed  by  Professor  Brauer  in 
the  end  of  1870.  Fig.  7  shows  the  same  as 
applied  to  a  vertical  gas  motor. 

a  is  the  brake  band  of  iron  or  steel  (i  to 
i|  mm.  thick,  and  30  to  80  mm.  wide  ac- 


cording  to  the  size  of  the  motor)  applied 
to  the  run  of  the  fly-wheel. 

Clamps  b,  which  grasp  the  fly-wheel  rim, 
prevent  the  side  displacement  of  the  band, 
and  serve,  on  account  of  their  great 
strength  of  metal,  as  plates  for  riveting 
securely  the  band,  c  is  the  arrangement 


Dynamometer,   Tests  for  Power.        37 

for  tightening,  d  the  hook  for  the  weight, 
e  the  provision  for  lubricating,  f  eyes  to 
which  are  attached  the  holding  ropes  r  as 
security  against  overrunning  of  the  brake 
in  the  case  of  lack  of  lubrication. 

For  the  proper  understanding  and  han- 
dling of  this  apparatus  the  following  points 


FIG.  8. 

may  be  noted  :  the  band  is  to  be  of  such 
a  length  that  even  when  the  tightening  nut 
is  at  its  furthest  limit  the  tongue  Z  (see 
Fig.  8)  will  overlap  the  other  end  of  the 
band  ;  the  direction  of  the  motion  of  the 
wheel  should  not  be  against  the  tongue  Z. 
The  hook  for  the  weight  must  be  so 
placed  on  the  horizontal  H  H  that  the  lat- 
ter will  not  overrun  this  line,  and  the 


38        Dynamometer,   Tests  for  Power. 

length  of  the  retaining  ropes  V  must  toe 
arranged  accordingly. 

If  the  hook  is  placed  above  the  horizon- 
tal the  arm  of  the  lever  is  shortened  and 
the  brake  resistance  diminished,  and  the 
brake  stays  in  this  higher  position. 

A  condition  of  the  utmost  importance 


FIG.  9. 

for  proper  and  correct  carrying  out  of  a 
brake  experiment  with  a  band  brake  is 
uniform  and  abundant  lubrication. 

The  arrangement  indicated,  at  G,  Fig. 
9,  should  be  put  in  operation  as  soon  as 
the  brake  has  been  fitted  up  and  the  motor 
is  running  under  normal  conditions. 

Before  the  beginning  of  the  experiment 
the  handle  of  the  coarse-threaded  screw  £ 


Dynamometer,   Tests  for  Power.        39 

is  turned  into  a  position  at  right  angles  to 
the  fly-wheel  and  the  arm  is  fastened  right 
and  left  to  the  staples  K  on  the  floor. 
Should  the  condition  of  lubrication  of  the 
brake  change,  and,  for  example,  the  weight 
tend  to  rise,  the  screw  S  also  moves  for- 
ward, and  since  the  arm  is  attached  to  the 
cord,  a  turning  of  the  screw  follows,  caus- 
ing a  loosening  of  the  band. 

Thus  the  brake  band  is  tightened  when 
the  weight  falls  and  loosened  when  it  rises. 

A  brake  fitted  up  in  the  above-described 
manner  can  after  the  proper  balance  is 
reached  remain  untouched  during  the 
whole  time  of  the  experiment. 

Working  with  the  Brauer  brake  is  usu- 
ally easy,  and  its  fitting  up  costs  very  lit- 
tle. 

If  the  armature  pieces  on  the  circumfer- 
ence are  of  equal  weight,  the  weight  of  the 
apparatus  itself  may  be  neglected.  The 
real  leverage  is,  as  in  the  Prony  brake, 
the  distance  between  the  perpendiculars 
passing  through  the  center  of  the  shaft  and 


4O        Dynamometer,    Tests  for  Poiver. 

of  the  weight  respectively  ;  it  would  be  a 
mistake  to  merely  measure  the  radius  of 
the  fly-wheel  added  to  the  distance  of  the 
hook  from  the  circumference. 

In  gas  motor  factories  where  brakes  are 
in  frequent  use  it  would  take  too  much 
time  in  each  particular  case  to  determine 
the  true  leverage  by  measurement  and 
each  time  to  go  through  a  calculation  of 
the  load.  The  installation  is  so  arranged 
that  for  each  size  of  motor  the  leverage 
remains  the  same,  and  is  always  braked 
while  running  at  the  same  number  of  turns  ; 
so  the  weight  of  the  counterbalance  gives 
at  once  the  power  of  the  motor. 

In  such  factories  the  arrangement  is 
more  or  less  modified  and  fitted  up  as 
shown  in  Fig.  10.  As  there  seen,  the  hook 
for  the  weight  is  attached  nearly  at  the 
highest  point  of  the  brake,  the  weight 
hangs  by  a  long  steel  band,  which  lies 
along  the  outer  circumference  of  the  same, 
and  however  the  brake  band  may  shift  in 
position,  the  line  of  suspension  remains 


Dynamometer,   Tests  for  Power.        41 

always  the  same,  the  weight  may  go  up  or 
down  ;  there  is  always  an  equilibrium  so 
long  as  the  stay  ropes  remain  slack. 


In  the  conduct  of  brake  experiments, 
especially  with  band  brakes,  certain  pre- 
cautions are  to  be  observed.  Above  all, 
band  brakes  must  fit  well  and  be  kept  in  a 
uniformly  good  state  of  lubrication.  If 
the  lubrication  is  neglected,  seizing  of  the 
band  is  to  be  feared.  In  such  cases  the 
brake  band  sticks  fast  momentarily  to  the 
wheel,  the  stay  bolts  must  either  break  or 


42        Dynamometer,   Tests  for  Power. 

pull  out,  and  the  weight  will  be  thrown 
off  from  the  wheel,  and  whoever  should 
be  hit  by  it  would  certainly  be  killed. 

Another  accident  may  occur  from  the 
breaking  of  the  brake  band.  A  case  is 
known  to  the  author  in  which  the  broken 
band  struck  the  operator  with  such  force 
on  the  head  from  behind  as-  to  fell  him  to 
the  ground,  and  he  narrowly  escaped  being 
caught  by  the  fly-wheel  and  thrust  into 
the  foundation  pit. 

It  is  to  be  preferred,  therefore,  that  a 
single  band  should  not  be  selected  in  test- 
ing lar^e  machines,  but  several,  side  by 
side,  bound  together  by  hoop  iron  so  as  to 
form  a  single  system. 

In  this  case  the  tightening  and  staying 
arrangements  are  to  be  duplicated. 

Further,  it  has  been  shown  that  iron 
should  not  run  on  iron,  or  steel  on  iron, 
but  the  whole  inner  brake  circumference, 
as  seen  in  Fig.  5,  should  be  furnished  with 
strong  sheet  copper  plates  about  i  to  \\ 
mm.  thick  and  10  cm.  long  and  about  15 


Dynamometer,   Tests  for  Poiver.        43 

cm.  apart,  so  that  only  copper  is  in  con- 
tact with  the  rim.  The  space  between 
each  two  copper  plates  should  be  well 
filled  with  thick  grease,  which  will  then  be 
a  provision  sufficient  for  a  long  run. 

Only  with  brakes  equipped  in  such  a 
manner  can  experiments  of  long  duration 
be  made  without  danger. 

By  such  an  arrangement  the  lubrication 
is  so  uniform  that  an  alteration  of  the  ten- 
sion during  the  whole  experiment  is  rarely 
necessary. 

Moreover,  a  hint  may  be  given  in  con- 
nection with  the  long  hanging  weight  in 
Fig.  10,  namely,  that  the  hanging  band 
should  be  screwed  and  fastened  to  the  en- 
circling band  of  the  fly-wheel  by  rivets, 
and  that  swinging  from  side  to  side  of  the 
weight  should  be  prevented.  If  the 
weighted  bag,  often  amounting  to  100  kilos 
(220  Ibs.),  should  fall  under  the  fly-wheel 
so  as  to  catch  in  the  arms,  it  may  be  thrown 
out  with  violence  into  the  neighborhood 
or  the  arms  of  the  fly-wheel  broken. 


44       Dynamometer,   Tests  for  Power. 

With  regard  to  the  duration  of  a  brake 
trial,  it  may  be  said  that  the  same,  espe- 
cially in  the  case  of  larger  motors,  is  limit- 
ed by  the  excessive  heating  of  the  fly- 
wheel rim.  If  this  precaution  is  neglected 
serious  damage  may  be  done  to  the  fly- 
wheel arms. 

As  mentioned  at  the  beginning  of  this 
chapter,  the  number  ot  revolutions  made 
by  the  motor  during  the  trial  is  to  be  ac- 
curately counted.  This  may  be  done  with 
sufficient  accuracy  with  a  revolution  coun- 
ter, an  instrument  to  be  lound  in  most  me- 
chanics* shops. 

Nearly  all  counters  are  put  in  action  by 
pressing.their  projecting  cornered  point  in 
the  center  of  the  motor  axle.  It  is  not 
often  possible  at  a  given  moment  to  strike 
the  center  of  a  quick-running  axle  with 
certainty  and  to  hold  the  instrument  in 
sufficiently  correct  relation  to  the  same  ; 
moreover,  it  demands  a  certain  effort  of 
the  body  to  maintain  the  original  pressure 
during  the  whole  time  of  the  trial. 


Dynamometer,    Tests  for  Poiver.          45 


For  long  trials  the  correctness  of  the  re- 
sults of  which  are  important  the  counter  is 
attached  to  a  lath  of  wood  which  is  of 
such  a  length  that  when  it  is  perpendicular 
to  the  floor  the  three-cornered  point  is 
exactly  of  the  height 
of  the  center  of  the 
motor  axle.  If,  then, 
the  lath  is  taken  in 
hand  and  the  foot 
placed  against  the 
lower  part  of  the 
lath  near  the  floor 
(see  Fig.  11)  the 
center  of  the  axle 
can  always  be  struck 
exactly  and  the 
counter  without  ef- 
fort held  in  correct  position,  so  that  every 
revolution  is  counted  with  certainty. 

Excessive  pressure  on  the  counter, 
whereby  bending  is  caused,  is  to  be  avoid- 
ed on  account  of  the  delicacy  of  the  in- 
strument, 


FIG.  ii. 


46       Dynamometer,   Tests  for  Power. 

Finally  the  bearing  of  the  spindle  of  the 
counter  should  receive  a  drop  of  neatsfoot 
oil  from  time  to  time. 

If  at  the  time  of  the  brake  test  the  gas 
consumption  is  to  be  determined,  then  a 
gas  meter  must  be  so  placed  that  during 
the  period  of  the  test  the  amount  of  gas 
passing  can  be  easily  read. 

As  it  is  generally  impossible  to  read  oft 
the  records  of  an  ordinary  gas  meter  at  a 
glance,  it  is  best  to  choose  the  moment 
when  the  hand  passes  through  zero  for 
commencing  the  experiment.  Then,  ac- 
cording to  the  size  of  the  motor,  the  time 
of  the  experiment  may  be  measured  by  the 
number  of  complete  revolutions  of  the 
dial. 

In  connection  with  brake  trials  the  fol- 
lowing remarks  may  be  made  : 

Above  all,  everything  about  the  motor, 
particularly  the  water  cooling  and  oiling, 
must  be  in  normal  condition  before  the  ex- 
periment is  begun — that  is  to  say,  it  must 
be  run  the  whole  time  at  full  power  under 


Dynamometer,    Tests  for  Power.        47 

the  brake  ;  the  brake  beam  must  be  nicely 
balanced  and  the  cooling  water  flow  away 
at  constant  temperature,  and  outside  of  the 
automatic  oiling  apparatus  no  further  oil- 
ing of  the  cylinder  and  connection-rod 
should  be  allowed. 

If  the  test  is  made  immediately  after  the 
delivery  of  the  motor  and  only  for  a  short 
period,  say  of  ten  minutes  about,  a  brake 
result  will  be  obtained  which  is  not  war- 
ranted by  a  performance  of  the  motor  on 
long-continued  runs,  and  one  much  more 
favorable  to  the  maker  than  to  the  pur- 
chaser. 

Two  persons  should  take  part  in  a  brake 
trial  :  one  to  watch  the  gas  consumption 
and  the  time,  who  can  indicate  the  begin- 
ning and  end  of  the  period  by  some  pre- 
concerted signal  such  as  a  call,  a  blow  of 
the  hammer,  etc.  ;  the  other  manipulates 
the  revolution  counter. 

As  the  time  of  the  test  must  often  be  de- 
termined exactly  within  a  few  seconds,  a 
stop  watch  should  be  used  which  can  be 


48        Dynamometer,  Tests  for  Power. 

started  or  stopped  by  a  pressure  of  the 
finger. 

However,  an  ordinary  watch  may  be 
used  if  it  is  provided  with  a  seconds  hand. 
Before  beginning  the  trial  the  watch  is 
fixed  so  that  the  larger  hand  is  exactly 
over  a  minute  mark  when  the  second  fin- 
ger points  to  the  beginning  of  a  new  min- 
ute. If  the  thumb  is  placed  on  the  watch 
glass  at  the  moment  of  commencing,  so  as 
to  indicate  the  position  of  the  second  fin- 
ger, it  is  easy  to  mark  the  time  of  the  be- 
ginning of  the  test  in  minutes  and  seconds, 
and  by  doing  the  same  thing  at  the  end  of 
the  trial  the  required  time  can  be  noted 
with  the  necessary  accuracy. 

After  the  end  of  a  brake  trial  the  load- 
ing weight  should  be  again  weighed.* 

i.  The  frictional  resistance  represented 
by  the  loading  weight. 


*  It  is  well  to  stop  the  motor  only  when  the  brake  is  loosened  ; 
also  the  weight  bag  should  be  taken  away  only  when  the 
motor  comes  to  a  standstill.  Then  all  data  are  obtained  for 
calculating  the  power  and  the  gas  consumption. 


Dynamometer,   Tests  for  Power.        49 

2.  The  velocity  at  which  the  resistance 
is  overcome,  obtained  by  multiplying  the 
effective  circumference  (in  feet)  of  the 
brake  band  by  the  total  number  of  revolu- 
tions and  divided  by  the  number  of  minutes 
occupied  in  the  test. 

Suppose,  for  example,  the  effective 
weight  to  be  52  Ibs.,  the  circumference  to 
be  12  ft.,  the  number  of  revolutions  1,500, 
and  the  time  occupied,  4  minutes  ;  then 

52  X  12  X  1500 

33000  X  4         =  7-°9  Horse  Power. 

The  brake  results  will  only  be  accurate 
when,  as  previously  stated,  the  loading 
weight  is  kept  in  perfectly  stable  equilib- 
rium ;  therefore  during  the  trial  the  tight- 
ening nuts  should  not  be  permanently  set, 
so  that  in  case  of  rising  or  falling  of  the 
weight  it  may  be  brought  to  the  proper 
position  by  a  quick  tightening  or  loosening 
of  the  nut.  A  very  delicate  adjustment 
may  be  made  by  a  light  tap  with  a  ham- 
mer upon  the  wing  nuts  on  one  side  or  the 


50       Dynamometer,   Tests  for  Power. 

other.  In  no  case  should  the  wing  nut  be 
taken  into  the  hand  during  the  trial,  for  the 
weight  of  the  arm  will  upset  all  certainty 
as  to  the  exact  balancing  of  the  brake  ar- 
rangement. 

For  the  purpose  of  comparing  different 
systems  of  motors  in  respect  to  gas  con- 
sumption this  should  be  determined  for 
i  hour  and  i  Horse  Power.  The  smaller 
the  motor  the  greater  the  gas  consumption 
for  i  Horse  Power  hour. 

By  the  brake  trial  the  brake  power  is 
determined — that  is,  the  useful  power 
which  the  motor  can  deliver,  the  waste 
work  consumed  in  friction  of  the  motor  is 
not  determined. 

The  total  work  obtained  from  the  fuel 
can  be  ascertained  only  by  an  indicator 
trial. 

By  comparison  of  the  results  of  the 
brake  trial  and  that  obtained  with  the  in- 
dicator an  opinion  as  to  the  efficiency  of 
the  motor  can  be  formed. 

With   good    workmanship   correct  run- 


Dynamometer,   Tests  for  Power.         5 1 

ning  motors  of  medium  power  consume  in 
friction  from  10  to  15  per  cent,  of  the  total 
work  obtained  from  the  gas. 

Moreover,  from  the  study  of  indicator 
diagrams  of  medium-sized  motors,  we  ob- 
tain the  following  disposition  of  the  heat 
generated  by  combustion  : 

1.  Turned  into  work 18  per  cent. 

2.  Carried    away   by    water 

jacket 50 

3.  By  exhaust 30 

4.  By  direct  radiation  from 

the  sides  of  cylinder  and 
water  jacket 02 


Total. .  ,100 


CHAPTER  III. 

THE  CARE   OF   GAS   MOTORS. 

THE  cardinal  virtue  of  a  good  gas  motor 
is  simplicity  of  management.  There  is  a 
continual  effort  in  this  respect  to  simplify 
and  improve  gas  motors.  In  fact  there 
are  to-day  motors  the  taking  care  of  which 
is  reduced  to  filling  up  the  oil  cups. 

Very  little  attention  is  required  to  keep 
them  in  good  running  order  ;  but  every 
three  or  four  weeks  the  motor  should  be 
thoroughly  overhauled,  and  the  exhaust 
and  slide  valves,  piston,  and  cylinder  prop- 
erly cleaned  from  all  dirt,  lampblack,  or 
congealed  and  dirty  oil. 

If  the  slight  attention  required  by  a  gas 
motor  is  intelligently  given  there  need  be 
no  fear  of  interruption  in  its  running.  The 


The  Care  of  Gas  Motors.  53 

first  necessity  for  long-continued  efficiency 
is  the  choice  of  a  really  good  oil  for  lubri- 
cating the  cylinder  and  slide  valve.  For 
the  high  temperatures  which  the  cylinder 
wall  and  especially  the  piston  of  a  fully 
loaded  gas  motor  have  to  contend  with, 
notwithstanding  the  water  cooling,  only 
such  oils  should  be  used  as  retain  their 
lubricating  properties  at  high  tempera- 
tures ;  they  should,  by  this  heating  up, 
neither  be  subject  to  quick  vaporization, 
nor  thicken  up  nor  form  lamp-black. 

Gas  motor  oil  consists  of  good  mineral 
oil  to  which  is  added  a  certain  quantity  of 
vegetable  or  animal  oil. 

Animal  oils  make  the  mixture  fluid  re- 
tain its  lubricating  properties  at  high 
temperatures,  and  form  a  little  but  hard 
oil  carbon.  The  mixture  is  rendered 
thicker  by  the  addition  of  vegetable  oil, 
which  tends  to  make  the  piston  air-tight, 
filling  up  the  grooves  between  the  piston 
and  cylinder  walls  ;  as  the  oil  carbonizes 
at  high  temperatures  more  easily  than 


54  The  Care  of  Gas  Motors. 

animal  oil,  more  carbon  is  formed  of  a 
porous,  spongy  structure. 

As  the  specific  gravity  of  the  various  oils 
used  for  a  gas  motor  oil  varies  after  stand- 
ing for  a  long  time,  a  separation  may  take 
place  ;  and  it  is  particularly  advised  that 
at  each  drawing  off  the  whole  oil  be  well 
stirred  up.  By  the  use  of  unsuitable  oil 
the  cylinder  and  piston  become  covered 
with  a  rusty  brown  layer. 

If  the  piston  of  a  motor  lubricated  with 
such  oil  is  withdrawn  it  is  found  to  be  cov- 
ered over  with  a  layer  of  rust,  the  oil  will 
have  formed  with  the  rust  a  thick,  streaky 
mass,  which  later  on  cooling  becomes  set 
and  hard,  the  grooves  are  filled  with 
the  same,  and  the  rings  themselves  set 
fast. 

If  the  piston  is  lubricated  only  for  a 
week  with  such  oil  it  may  be  confidently 
expected  that  the  motor  will  fail  to  work 
in  consequence  of  the  damage  to  the  cylin- 
der bore. 

Good  cylinder  oil  smeared  over'the  cylin- 


The  Care  of  Gas  Motors.  55 

der  and  piston  forms  a  grayish  film,  which 
disappears  with  the  warming  up  of  the 
motor,  so  that  the  polished  bluish  gray 
metallic  color  of  the  cylinder  and  piston 
is  again  visible.  All  the  piston  rings, 
even  the  farthest  in,  should  always  be 
found  to  be  easily  movable  when  the  pis- 
ton is  taken  out  for  cleaning. 

Oil  specially  prepared  for  gas  engines  is 
now  to  be  found  on  the  market  under  the 
name  "  gas  engine  cylinder  oil." 

Oil-feeding  apparatus,  and  still  more  oil- 
dropping  apparatus,  which  supply  less  oil 
than  when  the  same  is  full,  need  attention  ; 
it  is  well,  therefore,  to  fill  up  the  cups  at 
brief  intervals.  In  frosty  weather  the  oil 
should  be  warmed  in  the  can  before  filling 
the  oil  cups. 

It  is  advisable,  in  starting  the  motor,  to 
always  manipulate  all  the  necessary  han- 
dles in  the  same  order.  In  this  manner 
the  attendant  accustoms  himself  to  a  rou- 
tine that  makes  mistakes  nearly  impossi- 
ble ;  and  this  is  the  place  to  say  a  few 


56  The  Care  of  Gas  Motors. 

words  as  to  the  proper  order  in  which  the 
operations  should  be  performed. 

FOR  STARTING  THE  MOTOR. 

1.  Open  the  cock  of  the  rubber  bag. 

2.  Oil  ;  always  in  the  same  order. 

3.  Clean  the  exhaust  valve  spindle  with 
kerosene. 

4.  Light  the  gas  flame. 

5.  Put  in  place  the  provision  for  assist- 
ing in  turning  over  (starting  apparatus). 

6.  Open  the  gas  cock  of  motor  to  the 
point  marked  for  "  starting." 

7.  Turn  the  wheel  until  it  starts  off. 

8.  Gas  cock  full  open. 

9.  Put  back  starting  apparatus. 

10.  Turn  on  water  ;  examine  the  condi- 
tion of  the  water  in  cooling  apparatus. 

11.  Pass  belt  on  to  the  fast  pulley. 

STOPPING  THE  MOTOR 

1.  Turn  belt  off. 

2.  Close  cock  of  rubber  bag. 


The  Care  of  Gas  Motors.  57 

3.  Wipe  off  the  oil  from  the  slide  valve 
with  piece  of  waste. 

4.  Shut  off  the  cooling  water. 

5.  Stop  the  engine. 

6.  Close  the  gas  cock  for  the  motor  and 
lamp. 

7.  Place    piston   on    the   forward  dead 
point. 

8.  Draw  off  water  from  jacket. 

From  time  to  time  the  water  should  be 
drawn  from  the  gas  meter  and  replaced 
with  fresh  water. 

In  frosty  weather  the  water  should  be 
drawn  off  from  the  water  jacket  of  the  cyl- 
inder and  from  the  water  cooler,  and  the 
gas  meter  should  be  covered  with  straw  or 
felt. 

Cleaning  the  motor,  which,  according  to 
the  build  of  the  machine  and  the  quality  of 
the  oil  used,  will  have  to  be  undertaken  at 
various  intervals  of  time,  is  the  most  seri- 
ous part  of  the  attendant's  duty.  In  well- 
constructed  gas  motors  the  taking  apart, 
the  cleaning,  and  the  putting  together 


58  The  Care  of  Gas  Motors. 

again  are  accomplished  without  difficulty. 
Any  competent  workman  will  quickly  ac- 
quire the  necessary  handiness  and  be  able 
to  do  the  work  in  a  satisfactory  manner. 
It  is  necessary  to  clean  off  the  hardened  oil 
carbon  from  the  exhaust  and  slide  valves 
and  piston  from  time  to  time,  and  also 
from  the  interior  of  the  cylinder.  The 
slide  valve,  especially  the  igniter,  must  be 
well  cleaned  from  thickened  oil,  rust,  and 
dust. 

For  breaking  up  and  scratching  off  the 
carbon  from  the  exhaust  valve  box,  from 
the  ring  grooves  of  the  piston,  and  from 
the  piston  rings,  instruments  of  brass  or 
copper  should  be  used  ;  for  cleaning  out 
the  holes  and  channels  in  the  slide  valve, 
plugs  of  hard  wood  dipped  in  kerosene  are 
best. 

At  the  conclusion  the  seats  of  the  ex- 
haust valves,  piston,  piston  rings,  slide 
valve,  and  cylinder  should  be  well  wiped 
with  waste  moistened  with  kerosene. 

The  parts  removed  for  cleaning  should 


The  Care  of  Gas  Motors.  59 

not  be  placed  on  a  sandy  floor  or  leaned 
against  a  whitewashed  wall  ;  a  grain  of 
sand  left  sticking  is  often  sufficient  to  ruin 
the  slide  valve  or  piston. 

Nuts  set  fast  should  not  be  removed  by 
force.  If  kerosene  is  allowed  time  to  work 
into  them,  such  nuts  can  nearly  always  be 
easily  started.  If  the  bolt  is  smeared  with 
graphite,  or,  better,  with  a  paste  of  vase- 
line and  graphite,  setting  fast  of  the  nut 
is  not  to  be  feared. 

If,  on  cleaning  the  exhaust  valve  box, 
the  aperture  leading  to  the  silencing  pot 
is  found  to  be  clogged  up,  the  pipe  from 
the  valve  to  the  pot  must  be  taken  down 
and  cleaned  out  from  oil  carbon.  After 
cleaning  and  carefully  remounting  the  mo- 
tor, it  .should  be  immediately  run.  The 
fly-wheel  should  be  braked  with  a  plank 
until  full  power  is  developed  and  the  motor 
heated  up  to  a  normal  condition.  Only 
when  such  precautions  are  taken  can  we 
be  sure  that  it  will  perform  its  usual  duty 
without  trouble. 


60  The  Care  of  Gas  Motors. 

The  cleaning1  should  never  be  under- 
taken a  few  hours  before  the  time  for  use, 
for  it  cannot  be  foreseen  how  much  time 
will  be  required  nor  what  particular  cir- 
cumstances may  arise. 


CHAPTER  IV. 

THE  DERANGEMENT  OF  GAS  MOTORS. 

NEARLY  all  the  derangements  to  which 
gas  motors  are  liable  are  due  to  leakage  of 
the  valves,  slide  valve,  and  piston. 

While  a  steam  engine  with  leaking  slide 
valve,  valves,  etc.,  performs  its  work  bad- 
ly, the  gas  motor  under  similar  circum- 
stances comes  to  a  standstill.  The  reason 
for  this  peculiarity  of  the  gas  motor  is 
quite  obvious — it  is  without  the  power 
reservoir  which  the  boiler  furnishes  to  the 
steam  engine. 

The  gas  motor  takes  its  fuel  for  each 
particular  combustion  and  mixes  it  with 
precisely  the  required  quality  of  air,  and 
is,  therefore,  ready  at  any  moment  for 
beginning  work.  Unfortunately,  to  this 
valuable  quality  a  serious  condition  is  ap- 


62       The  Derangement  of  Gas  Motors. 

pended.  It  may  be  said  of  a  gas  motor 
that  it  lives  from  hand  to  mouth  ;  what  it 
obtains  at  one  moment  is  expended  the 
next  ;  when  the  supply  of  nourishment  is 
interrupted,  or  is  lost  before  it  can  be  con- 
sumed, the  life  of  the  motor  is  itself  inter- 
rupted. 

As  is  well  known,  it  is  difficult  and  often 
impossible  to  determine  by  smelling  the 
place  of  escape  of  gas,  which  is  not  visible, 
so  that  it  is  not  easy  to  locate  derangement 
in  running  caused  by  want  of  tightness. 
To  arrive  quickly  at  a  conclusion  in  this 
matter  it  is  necessary  to  go  to  work  sys- 
tematically. The  classification  in  the  last 
chapter  will  furnish  the  necessary  hints  for 
a  systematic  search  for  faults. 

In  the  first  place,  a  general  rule  for  ex- 
amining a  defective  gas  motor  may  be 
stated. 

When  a  gas  motor  refuses  to  operate, 
the  first  thing  to  be  done  is  to  turn  over 
the  fly-wheel. 

In  all  cases  the  contents  of  the  cylinder 


The  Derangement  of  Gas  Motors.      63 

will  be  compressed.  If  the  motor  leaks, 
then  either  a  slight  resistance  only  is  felt 
or  the  same  disappears  very  quickly.  If 
by  these  means  the  existence  of  a  leakage 
is  established,  the  same  may  be  easily  lo- 
cated by  proceeding  step  by  step  in  the 
manner  subsequently  described. 

The  following  are  the  principal  faults 
met  with  in  a  gas  motor  : 

The  motor  refuses  to  work. 

Difficult  starting. 

Unaccountable  stopping. 

Irregular  running. 

Loss  of  power. 

Knocking  in  the  air-pot  (back  firing). 

Shocks  in  the  motor. 

Each  particular  trouble  may  be  caused 
by  special  circumstances  ;  the  probable 
complications  must  be  settled  for  each  case. 

i.  THE  MOTOR  REFUSES  TO  WORK  IN 
CONSEQUENCE  OF  LEAKY  EXHAUST  VALVE. 

Three  kinds  of  leakage  may  be  distin- 
guished ; 


64       The  Derangement  of  Gas  Motors. 

a.  The  valve  has  hung  itself  up  while  in 
operation. 

b.  The  exhaust  valve  spring  is  too  weak. 

c.  The  slide  valve  seat  is  damaged. 

(a)  Hanging  up  of  the  exhaust  valve  is 
nearly  sure  to  occur  after  the  motor  has 
been  standing  for  some  time.  The  valve 
must  be  made  of  steel  or  wrought  iron  to 
stand  the  high  temperature. 

The  products  of  combustion  consist  prin- 
cipally of  water  vapor  and  carbonic  acid, 
from  which  it  is  obvious  that,  after  stand- 
ing for  a  long  time,  they  must  become 
coated  with  rust  and  their  freedom  of 
movement  hindered. 

If  it  is  attempted  to  start  the  motor 
under  such  circumstances,  the  exhaust 
valve  not  being  tight,  a  portion  of  the  un- 
burned  mixture  escapes  during  the  com- 
pression period  into  the  silencing  pot  and 
the  exhaust  pipe.  As  the  firing  necessarily 
follows,  this  is  communicated  to  the  mix- 
ture drawn  out  through  the  leaking  valves, 
and  a  strong  explosion  takes  place  through 


The  Derangement  of  Gas  Motors.      65 

the  exhaust  valve.  If  several  revolutions 
occur  before  the  igniting  apparatus  oper- 
ates, the  explosion  may  have  the  force  of 
a  cannon  shot  and  alarm  the  whole  neigh- 
borhood. 

Every  good  gas  motor  should  be  provid- 
ed with  a  means  of  avoiding  this  fault.  It 
consists  in  an  oil  groove  for  the  exhaust 
valve  spindle. 

Every  morning,  before  starting,  a  little 
kerosene  is  to  be  trickled  into  this  oil  hole 
and  the  valve  moved  backward  and  for- 
ward. 

By  these  means  the  proper  starting  up 
of  the  motor  is  ensured,  nor  is  a  derange- 
ment to  be  feared. 

For  applying  the  kerosene,  it  is  best  to 
use  the  ordinary  squirt  can,  such  as  is  gen 
erally  used  for  sewing  machines.  Oil 
should  not  be  used  for  lubricating  the  ex- 
haust valve  spindle,  for  this  would  produce 
an  effect  the  opposite  of  that  desired  ;  for, 
while  kerosene  is  evaporated  without  resi- 
due when  the  valve  is  warmed,  oil  leaves  a 


66       The  Derangement  of  Gas  Motors. 

carbon  deposit  which  impedes  the  action 
of  the  valve  as  much  as  rust. 

(b)  The  indications  are  different  when  the 
spring  of  the  exhaust  valve  is  so  weakened 
by  the  heat  or  otherwise  that  the  valve  is 
lifted  during  the  suction  period  by  the  in- 
flowing air.  In  this  case  none  of  the  mix- 
ture passes  into  the  exhaust  pipe,  but  the 
proper  gas  proportions  will  be  influ- 
enced. 

Together  with  the  gas  mixture  drawn 
through  the  mixing  apparatus  a  back  draft 
through  the  exhaust  valve  comes  which 
makes  the  charge  inexplosive.  On  fur- 
ther revolutions  of  the  fly-wheel  the  same 
is  repeated,  with  the  difference,  however, 
that  now  the  unexploded  exhaust  forms  a 
strong  mixture,  and  the  new  charge  is 
formed,  not  with  pure  air,  but  with  this 
already  strong  mixture.  With  each  mis- 
fire, the  gas  mixture  in  the  cylinder  be- 
comes richer,  until  at  length  it  is  fired 
and  a  power  stroke  comes  about.  The 
motor,  however,  does  not  operate  continu- 


The  Derangement  of  Gas  Motors.      67 

ously,  but  after  a  time  the  above-mentioned 
conditions  recur. 

After  four,  six,  eight,  or  more  revolu- 
tions the  charge  is  enriched  to  the  firing 
point.  It  is  possible  that  the  power  stroke 
is  sufficient  to  give  the  motor  momentum 
enough  to  carry  it  over  the  misfires  ;  the 
motion  will  then  be  kept  up,  but  little  or 
no  power  will  be  rendered. 

The  phenomenon  of  periodic  misfires 
may  be  brought  about  by  other  faults  ;  it 
alone,  therefore,  is  not  a  proof  that  an  ex- 
haust valve  spring  is  weak  ;  this  may  be 
seen  to  be  the  case  when  the  suction  period 
is  accompanied  by  a  vibration  of  the  valve 
on  the  valve  seat. 

(c]  Finally,  if  the  valve  face  is  damaged 
or  the  closing  of  the  same  hindered  by  for- 
eign matter,  the  thumping  in  the  exhaust 
pipe  is  the  same  as  when  the  valve  is  set 
fast ;  simply  freeing  the  spindle  with  kero- 
sene is  not  now  sufficient.  If  the  pound- 
ng  in  the  exhaust  valve  is  heard  and  a 
vibration  of  the  valve  spindle  is  felt,  then 


68       The  Derangement  of  Gas  Motors. 

the  valve  surface  is  damaged,  and  the 
valve  must  without  further  waiting  be 
taken  out  and  wiped  ;  the  substance  im- 
bedded in  the  valve  seat  can  by  firm  rub- 
bing of  the  valve  cone  be  discovered  and 
easily  removed. 

2.  THE  MOTOR  STOPS  WORKING  BY  REA- 
SON OF  LEAKING  INLET  VALVE  OR  SLIDE. 

It  is  evident  that  with  a  leaking  inlet 
valve  the  unexploded  mixture  will,  during 
the  compression  period,  be  forced  back 
through  the  air  pipe.  The  next  inspira- 
tion, therefore,  is  made  up,  not  of  a  mix- 
ture of  gas  and  air,  but  of  gas  mixture 
and  gas,  for  the  air  pipe  contains  a  gas 
mixture  of  such  richness  that  it  burns  either 
not  at  all  or  with  slight  change  of  pressure. 

External  indications  of  this  fault  are  yel- 
lowish red  exploding  flame  in  the  lighting 
apparatus  and  a  smell  of  gas  in  the  exhaust 
pot.  If  a  thread  of  waste  or  strip  of  paper 
is  held  over  the  air  opening  during  com- 
pression a  back  draft  will  be  felt. 


The  Derangement  of  Gas  Motors.      69 

3.  INTERRUPTION  OF  THE  MOTOR  IN  CON- 
SEQUENCE OF  THE  SETTING  FAST  OF  THE 
LIGHTING  VALVE. 

When  the  motor  stands  for  some  time 
without  working  the  suction  valve,  like  the 
exhaust  valve,  may  be  rusted  up,  and  so  re- 
main hung  up  when  the  engine  is  started. 
Slide  valve  igniters  easily  cut  in  running, 
and  the  metal  cuttings  fall  on  to  the  valve 
surface,  set  fast  there,  and  give  rise  to 
leakage. 

The  indications  of  these  faults  are  very 
characteristic  :  sharp  hissing  of  the  igniter 
during  the  whole  compression  period, 
drawing  in  of  the  ignition  flame,  and 
thumping  or  gurgling  in  the  air  pot  during 
the  suction  period. 

4.  FAILURE    TO    OPERATE   IN    CONSE- 
QUENCE OF  INCREASED  GAS  PRESSURE. 

For  every  gas  motor,  after  the  fitting  up 
is  finished,  during  the  first  trial  run,  the 
gas  mixture  will  be  according  to  the  qual- 
ity of  gas  and  corresponding  to  the  regu- 


70       The  Derangement  of  Gas  Motors. 

lar  gas  pressure,  and  the  proportion  of  the 
air  charge  exactly  regulated.  If  these 
conditions  are  changed  the  proper  running 
of  the  motor  will  be  upset. 

If,  for  example,  the  gas  pressure  in- 
creases, then  on  suction  the  mixture  is  too 
rich  in  gas,  so  that  though  it  may  be  in- 
flammable, the  explosion  follows  without 
the  change  of  pressure  necessary  for  actu- 
ating the  motor. 

Other  indications  of  this  derangement 
are  as  follows  :  In  the  exhaust  period  a 
thick  black  smoke  is  discharged  without 
much  noise,  the  rubber  bag  is  inflated, 
the  ignition  flame  burns  higher,  and  the 
flame  in  the  ignition  apparatus  has  an  un- 
usually yellow  color. 

To  operate  the  motor  in  spite  of  the  in- 
creased pressure,  which  can  hardly  be 
altered,  the  attendant  requires  a  helper 
whom  he  should  station  at  the  gas  cock 
with  instruction  to  open  the  same  slowly 
while  he  himself  vigorously  turns  the  fly- 
wheel. The  gas  cock  should  not  be  opened 


The  Derangement  of  Gas  Motors.      71 

until  three  or  four  revolutions  have  been 
made.  The  cock  must  be  adjusted  .until 
the  motor  runs  as  before,  and  even  for  the 
normal  speed  of  the  motor  the  cock  will 
not  be  full  open.  This  kind  of  disturbance 
cannot  occur  when  a  pressure  regulator  is 
used. 

5.  STOPPAGE  BY  REASON  OF  DERANGE- 

MENT  OF  THE  GAS  METER. 

If  the  drawing  off  of  the  surplus  water 
from  the  meter  and  refilling  with  fresh 
water  have  been  neglected  the  gas  is  cut 
off  and  the  motor  cannot  operate.  The 
shrunken  gas  bag  indicates  at  once  the 
cause  of  the  trouble  ;  the  gas  bag  should 
be  the  first  thing  to  observe.  Very  fre- 
quent cause  for  stoppage  of  the  motor  is 
that  the  main  cock  or  the  gas  bag  cock  has 
not  been  opened,  which  circumstance  is 
also  indicated  by  the  shrunken  condition 
of  the  gas  bag. 

6.  STOPPAGE  OF   THE  MOTOR  ON  Ac- 


72       The  Derangement  of  Gas  Motors. 

COUNT  OF  WATER  COLLECTED  IN  THE  EX- 
HAUST POT. 

If  we  neglect  to  draw  off  the  condensa- 
tion collected  as  water  in  the  exhaust  pot 
it  may  often  happen,  especially  in  winter, 
that  it  reach  such  a  height  as  to  stop  up 
the  exhaust  pipe.  When  the  motor  runs 
slowly,  as  at  the  starting,  the  water  runs 
by  the  open  exhaust  valve  directly  into  the 
cylinder.  Under  such  circumstances,  if 
the  first  ignition  takes  place,  the  pulverized 
or  vaporized  water  hinders  the  further  for- 
mation of  an  explosive  mixture  and  the 
motor  will  not  start. 

Indications  of  this  fault  are  :  spurting 
out  of  water  from  the  ignition  port  between 
the  slide  valve  ;  dampness  of  the  cylinder 
walls— water  jets  out  of  the  exhaust  pipe  ; 
when  a  porcelain  ignition  tube  is  used 
it  is  frequently  burst.  For  remedying 
this  accident  the  cock  of  the  exhaust  pot 
should  be  opened;  the  water  in  the  cylinder 
and  all  valve  boxes  cleared  out  with  waste. 

When  this  accident  occurs  for  the  first 


The  Derangement  of  Gas  Motors.      73 

time  there  is  "usually  a  fear  that  the  cylin- 
der may  have  burst ;  this  is,  however, 
very  seldom  the  case* 

7.  DIFFICULT  STARTING  OF  THE  MOTOR 
IN  CONSEQUENCE  OF  LEAKY  PISTON. 

Every  gas  motor  cylinder  must  in  the 
course  of  years  deteriorate  and  the  piston 
become  leaky.  This  want  of  tightness  in- 
fluences the  mixture  of  gas  and  the  condi- 
tion of  compression,  particularly  at  start- 
ing, at  which  time  the  movement  of  the 
piston,  in  comparison  with  the  normal  ve- 
locity, is  very  slow.  A  small  space  between 
the  piston  and  cylinder  wall  is  then  suffi- 
cient for  bringing  into  the  cylinder  during 
suction  a  considerable  quantity  of  "  side 
draft,"  while  during  the  ti  me  of  compression 
a  still  greater  quantity  of  the  unburned  gas 
mixture  escapes,  At  the  moment  of  igni- 
tion we  have  a  slightly  compressed  weak 
mixture,  which  often  is  inexplosible. 

Only  after  a  considerable  number  of 
revolutions,  when  the  piston  reaches  a 


74      The  Derangement  of  Gas  Motors. 

greater  velocity  through  energetic  turn- 
ing of  the  fly-wheel,  and  the  influence  of 
leakage  is  thereby  weakened,  is  it  possible 
to  obtain  a  better  mixture  which  is  explosi- 
ble  and  which  expands  with  sufficient  force 
to  set  the  motor  going. 

As  remedies  for  this  fault,  when  chronic 
in  a  gas  motor,  may  be  mentioned  : 

1.  Leaving  out  of  use  the  starting  gear  so 
as  to  compress  the  whole  volume  of  the 
cylinder. 

2.  Use  of  thick  lubricating  oil.     Before 
starting  smear  the  piston  with  rich  oil  and 
run  it  slowly  backward  and  forward  sev- 
eral times,  keeping  the  gas  cock  closed  so 
that  the  cylinder  wall  and  piston  are  coat- 
ed with  a  thick  layer  of  oil. 

3.  Lifting  the  (inlet)  valve  with  the  hand 
during  the  suction  period.     By  this  means 
the  vacuum  caused  by  the  suction  is  less- 
ened,  a  greater  quantity  of  the  mixture 
taken  in,  and  the  first  starting  stronger. 

This  last  means  generally  acts  with  re- 
markable promptness. 


The  Derangement  of  Gas  Motors.      75 

8.  DIFFICULTY  IN  STARTING  IN  CONSE- 
QUENCE OF  DIRTY  SLIDE  VALVE. 

In  many  motors  the  lubricating  oil  is 
led  from  a  general  lubricating  apparatus 
to  the  slide  valve  and  piston.  On  stop- 
ping, the  pipes  are  filled  with  a  consider- 
able quantity  of  oil,  which  gradually  leaks 
out,  and  the  channels  and  grooves  of  the 
igniting  apparatus  in  the  slide  valve  are 
filled.  If  after  standing  some  time  it  is  at- 
tempted to  start  up  the  engine  many  futile 
turns  may  have  to  be  given  in  order  that 
the  oil  may  be  blown  out  from  the  main 
channels  and  grooves  of  the  slide  valve. 
As  must  be  well  known  to  many  owners 
of  gas  engines,  this  fault  may  be  easily 
remedied  if  on  stopping  a  small  piece  of 
wood,  which  will  absorb  the  escaping  oil, 
be  placed  under  the  mouth  of  the  tube 
feeding  the  slide  valve. 

9.  DIFFICULTY  IN  STARTING  IN  CONSE- 
QUENCE OF  AIR  IN  THE  GAS  PIPE. 

It  is  a  matter  of  common  experience  that 


76       The  Derangement  of  Gas  Motors. 

unused  pipes  leading  from  the  street  mains 
in  time  fill  with  air.  It  would  be  a  diffi- 
cult undertaking  to  attempt  to  start  up  at 
once  a  motor  which  has  been  idle  some 
time.  The  total  contents  of  the  piping 
would  have  to  be  pumped  out  by  turning 
the  motor  by  hand  before  ignition  is  to  be 
thought  of. 

In  all  such  cases  the  piping  must  be 
blown  out  before  starting  by  holding 
open  the  gas  valve,  mixing  valve,  etc., 
or  a  cock  especially  provided  for  that  pur- 
pose. 

Moreover,  a  small  leak  in  the  gas  piping 
which  cannot  perhaps  be  detected  by  light- 
ing is  often  sufficient  to  fill  the  connecting 
pipe  over  night  with  air.  If  it  is  noticed 
that  the  motor,  notwithstanding  careful 
preparation,  starts  with  more  than  ordi- 
nary difficulty  in  the  morning,  we  may  be 
pretty  sure  that  there  is  air  in  the  pipe. 
A  good  blowing  out  before  starting  will 
always  be  advisable. 


The  Derangement  of  Gas  Motors.      77 

10.  UNACCOUNTABLE  STOPPING  OF  THE 
MOTOR. 

Without  counting  stoppages  which  arise 
from  the  breaking  of  springs,  stoppage  in 
gas  meter,  etc.,  we  shall  in  this  place  speak 
only  of  such  derangements  as  arise  from 
the  extinction,  flickering,  or  fluttering  of 
the  igniting  flame. 

In  the  ignition  apparatus  most  in  use  at 
the  present  time  the  flame  can  be  easily 
put  out  by  the  operation  of  the  engine  it- 
selt.  If  the  springs  of  the  slide  valve  or 
ignition  valve  are  too  weak,  the  latter  may 
by  great  increase  of  pressure,  such  as  oc- 
curs after  misfires  in  the  cylinder,  be 
thrown  off  their  seats.  The  excessive 
amount  of  igniting  gas  now  flowing  out 
may  be  sufficient  to  blow  out  the  jet.  The 
same  thing  occurs  when  the  ignition  valve 
is  not  tight.  The  jet  may  also  be  blown 
sufficiently  to  one  side  to  miss  the  ignition, 
and  thus  cause  stoppage.  The  opening  of 
doors  or  windows,  the  motion  of  the  fly- 


78       The  Derangement  of  Gas  Motors. 

wheel  may  cause  drafts  which  bring  about 
such  a  condition. 

A  stoppage  quite  unintelligible  to  the 
attendant  often  occurs  when  the  motor  is 
working  with  a  full  load,  arising  from  the 
falling  off  of  the  gas  pressure  caused  either  by 
increased  consumption  in  the  neighborhood 
or  by  some  derangement  at  the  gas  works. 

If  a  rapid  examination  of  the  motor  is 
made,  everything  appears  to  be  in  order  ; 
the  ignition  flame  is  burning  and  the  motor 
is  easily  set  in  motion  again,  and  there  is 
no  indication  of  anything  unusual.  If  the 
attendant  waits  a  short  time,  however,  af- 
ter starting  the  motor  he  will  observe  that 
the  ignition  jet  becomes  weaker  and  weak- 
er, until  finally  misfires  occur. 

Provided  that  the  gas  piping  is  large 
enough,  this  fault  may  be  remedied  by  put- 
ting in  two  or  three  gas  bags. 

ii.  IRREGULAR  RUNNING  BROUGHT 
ABOUT  BY  MISFIRES. 

Leaking  or  dirty  slide  valves,   leaking 


The  Derangement  of  Gas  Motors.      79 

ignition  valve,  flickering  or  low-burning 
ignition  flame  are  generally  the  cause  of 
misfires. 

The  indications  of  this  kind  of  trouble 
are  very  characteristic  and  easily  recog- 
nized. Dull  noises  are  heard  in  the  motor 
followed  by  a  whistling  noise.  Slide 
valve  or  ignition  valve  may  be  thrown  off 
its  seat  and  the  highly  compressed  explo- 
sive gases  rush  out  with  a  loud  noise. 

This  trouble  may  be  obviated  by  proper 
installation  and  protection  of  the  ignition 
flame,  cleaning  the  valves,  or  adding  a 
second  gas  bag. 

12.  IRREGULAR  RUNNING  IN  CONSE- 
QUENCE OF  DEFECTIVE  OPERATIONS  OF 
THE  GOVERNOR. 

Thickened  lubricating  oil  or  sticking  of 
the  governor  spindle  often  occasions  a 
considerable  irregularity  in  the  rate  of  run- 
ning of  the  motor.  Sticking  may  occur 
through  worn-out  pins  of  links  or  omis- 
sion of  oiling. 


8o       The  Derangement  of  Gas  Motors. 

The  cause  of  this  trouble  is  easily  found 
out  by  the  fact  that  the  periods  of  regulat- 
ing are  lengthened,  due  to  sluggish  action 
of  the  governor. 

13.  Loss  OF  POWER  BY  LEAKY  PISTON. 

The  leaky  condition  of  the  piston  is  dis- 
covered by  the  hissing  and  knocking  in 
the  cylinder,  by  the  peculiar  smell  of  gas 
and  burned  oil,  by  a  heavy  atmosphere  in 
the  neighborhood  of  the  motor,  and,  above 
all,  by  the  constantly  increasing  gas  bill. 

The  remedying  of  the  evil  may  become 
a  serious  matter  ;  above  all  things,  as  al- 
ready stated,  the  use  of  improper  oil  is 
likely  to  cause  this,  also  the  blame  may  be 
placed  to  insufficient  oiling  on  account  of 
oversight  or  neglect,  in  cleaning  the  cyl- 
inder oiling  apparatus,  as  well  as  insuffi- 
cient cooling  of  the  cylinder.  The  water 
should  flow  away  at  a  temperature  not 
above  70°  C.  (160°  Fahr.)  in  the  cooling 
tanks  ;  the  water,  even  in  the  hottest  sum- 
mer, should  never  rise  above  70°  C. 


The  Derangement  of  Gas  Motors.      81 

For  some  time  the  loss  may  be  cured  by 
putting  in  new  piston  rings  ;  finally,  how- 
ever, the  cylinder  must  be  rebored  and  a 
new  piston  provided.  If  the  motor  is 
chosen  of  such  a  size  that  the  full  power  is 
easily  furnished,  so  that  the  cut-off  of  the 
governor  operates  after  moderate  periods 
of  rest,  the  engine  not  only  works  cooler, 
but  in  a  manner  most  favorable  to  the 
proper  distribution  of  the  lubricating  oil 
in  the  cylinder. 

A  gas  motor  under  such  circumstances 
remains  a  long  time  in  good  condition,  and 
a  reboring  of  the  cylinder  is  often  neces- 
sary only  after  ten  years  of  service,  while 
one  driven  too  hard  may  require  this  cost- 
ly repair  after  two  or  three  years'  running. 

14.  Loss  OF  POWER  BY  FORMATION  OF 
WEAK  MIXTURE. 

Diminished  gas  pressure,  stopped-up  gas 
piping  or  too  small  opening  of  the  gas  cock 
may  give  rise  to  weak  gas  mixture.  The 
mixture  is  indeed  explosive,  but  burns 


82       The  Derangement  of  Gas  Motors. 

slowly    and    with    less   change    of    pres- 
sure. 

Indications  :  Sharp  reports  in  the  ex- 
haust ;  from  time  to  time  a  gurgling  sound 
or  weak  crackling  in  silencing  pot. 

15.  Loss  OF  POWER  THROUGH  THROT- 
TLING OF  THE  SUPPLY. 

The  cause  of  diminished  supply  in  the 
suction  capacity  of  the  motor  arises  from 
the  spring  of  the  mixing  valve  or  suction 
valve  being  too  strong. 

The  mixture  itself  is  normal  in  constitu- 
tion and  burns  sufficiently  promptly,  but 
the  ignition  pressure  is  less. 

Indications  :  Weakened  noise  in  the  ex- 
haust. 

16.  Loss  OF    POWER   THROUGH    BACK 
PRESSURE  OF  THE  BURNED  PRODUCTS. 

By  diminished  area  of  the  exhaust  pipe  a 
back  pressure  is  set  up  on  the  piston  ; 
moreover,  since  a  large  quantity  of  the 


The  Derangement  of  Gas  Motors.      83 

burned  products  remain  in  the  cylinder, 
the  quality  of  the  mixture  is  changed. 

By  the  wear  of  the  motion  pin  of  exhaust 
valve  the  time  of  exhaust  of  most^notors 
is  shortened,  and  in  consequence  there  re- 
mains behind  in  the  cylinder  a  greater 
quantity  of  burned  gas. 

Indications  :  Long-drawn-out  exhaust 
from  time  to  time  ;  gurgling  in  the  ex- 
haust pot ;  smoking  of  the  piston  ;  dry 
cylinder  walls. 

17.  Loss  OF  POWER  THROUGH  LATE 
IGNITION. 

By  the  metallic  wear  and  tear  of  the 
ignition  mechanism  the  alteration  of  the 
time  of  ignition  is  usually  such  as  to  make 
it  later.  Even  a  slight  lateness  in  the  igni- 
tion operates  disproportionately  unfavor- 
able in  the  utilization  of  the  burning  mix- 
ture. From  time  to  time  the  condition  of 
the  lighting  should  be  regulated. 

Indications  of  late  ignitions  are  exhaust 
with  loud  noise  and  thumping  in  the  motor. 


84       The  Derangement  of  Gas  Motors. 

1 8.  LOUD    REPORTS    IN   THE  EXHAUST 
POT  (BACK  FIRING). 

Arise  generally  from  the  neglect  to  open 
the  gs&  cock  fully  after  starting  up.  A 
weak,  slow-burning  mixture  is  formed 
which  continues  to  burn  in  the  clearance 
space  during  the  following  period  of  suc- 
tion when  the  gas  mixture  comes  in.  This 
latter,  as  soon  as  it  comes  in  contact  with 
the  burning  gas,  is  ignited  and  rushes  with 
a  loud  thump  into  the  exhaust  pot. 

In  motors  with  slide  valve  ignition  this 
circumstance  is  already  referred  to  ;  it  may 
also  be  sought  for  in  the  leaking  of  the 
ignition  slide  valve.  It  can  be  easily  seen 
in  such  cases,  for  the  ignition  flame  is 
drawn  into  the  valve  and  the  charges  ig- 
nited while  it  is  passing  in  through  the 
open  mixing  apparatus. 

19.  KNOCKING  AND  THUMPING  IN  THE 
MOTOR. 

A  loose  key  of  the  fly-wheel,  loosening 
of  the  main  bearing  cap  or  of  the  bolts  used 


The  Derangement  of  Gas  Motors.      85 

on  the  piston  cause  a  severe  shock  in  the 
motor  at  the  time  of  ignition.  It  is  not 
always  easy  to  find  the  seat  of  the  evil.  A 
proceeding  likely  to  aid  is  as  follows  : 
Turn  off  the  light  and  the  gas  cock  and 
give  a  jerking  backward  motion  to  the  fly- 
wheel, at  the  same  time  laying  the  hand 
carefully  on  all  those  parts  where  it  is  be- 
lieved the  knocking  can  be  found.  The 
blowing  out  of  oil  from  the  joints  of  the 
connections  in  question  which,  during  the 
jerking  motion,  ooze  out  and  flow  back, 
often  indicate  the  origin  of  the  trouble. 

Early  ignition  likewise  causes  severe 
thumping  in  the  motor,  which  is  particu- 
larly observed  at  slow  speed  shortly  after 
starting  or  after  a  misfire. 

If  the  under  side  of  the  cylinder  bore  is 
much  worn  a  dull  thud  is  heard  in  the  mo- 
tor. At  each  working  stroke  the  piston  is 
thrown  violently  from  one  side  of  the  cyl- 
inder to  the  other. 

When  this  noise  is  heard  it  is  high  time 
to  have  the  cylinder  rebored. 


CHAPTER  V. 

DANGERS  AND  PRECAUTIONS  IN  CONNEC- 
TION WITH  THE  RUNNING  OF  GAS  MO- 
TORS. 

LIKE  every  other  machine,  the  gas  en- 
gine has  ,dangers  peculiar  to  itself,  of 
whose  existence  every  one  who  has  to 
deal  with  it  should  be  acquainted. 

The  dangers  which  leaking  gas  fittings 
occasion  are  well  known  ;  their  prevention 
in  the  case  of  a  gas  engine  demands  greater 
care  than  that  of  ordinary  gas  fixtures, 
which  are  usually  tested  and  carefully 
erected.  In  the  gas  engine  it  is  frequently 
necessary  to  loosen  them.  After  each  new 
assembling  of  valves  and  gas  pipes,  etc., 
all  joints  should  be  carefully  tested  as  to 
their  tightness,  and  especially  the  freedom 
from  leakage  of  the  gas  bag  maintained. 


Dangers  and  Precautions.  87 

Here  it  may  be  remarked  that  when  gas 
piping  is  once  coupled  up  it  is  very  diffi- 
cult to  locate  leaks  by  lighting  up  the  es- 
caping gas.  Small  leaks  especially  cannot 
be  found  at  all  in  this  way,  for  the  opening 
immediately  after  the  putting  up  will  pass 
only  air  or  an  incombustible  gas  mixture. 

Better  evidence  of  leaking  is  obtained  by 
the  use  of  soapsuds  or  oil,  with  which 
bubbles  are  made  when  placed  over  even 
the  smallest  leak. 

The  gas  mixture  remaining  behind  in 
the  clearance  space  and  the  valve  cham- 
bers of  a  gas  engine  during  a  period  of  rest 
retain  perpetually  their  explosive  capaci- 
ties. 

When  proceeding  to  examine  a  gas  mo- 
tor, therefore,  it  should  always  be  taken 
for  granted  that  all  the  clearance  spaces 
without  the  same  are  filled  with  explosive 
gas.  Before  anything  is  opened  or  taken 
apart  the  gas  flame  should  always  be  put 
out  and  the  gas  cock  on  the  supply  pipe  to 
the  motor  closed.  Only  after  giving  the  fly- 


88  Dangers  and  Precautions. 

wheel  five  or  six  turns  can  one  be  sure  that 
there  is  no  explosible  gas  mixture  in  the  inte- 
rior of  the  motor. 

It  may  be  specially  mentioned  as  a  very 
dangerous  proceeding  to  take  out  the  pis- 
ton without  first  putting  out  the  light  and 
closing  the  gas  cock. 

It  is  always  possible  that  the  motor  stops 
in  such  a  position  or  is  turned  over  in  such 
a  manner  that  while  the  piston  is  being 
drawn  out  the  ignition  flame  may  be 
drawn  into  the  interior  of  the  cylinder,  and 
the  consequent  explosion  of  its  contents 
may  throw  the  piston  out  with  such  force 
that  a  serious  accident  may  be  caused. 

Equally  bad  consequences  may  follow 
when,  on  taking  out  the  exhaust  valve  of 
a  motor  at  rest,  a  flame  is  introduced  into 
the  valve  casing,  as  is  frequently  neces- 
sary for  examining  more  closely  into  the 
tightness  of  the  valve.  The  gas  mixture 
ignited  in  this  manner  will  shoot  out  as  a 
long  flame  from  the  valve  opening  and 
may  give  rise  to  serious  burning. 


Dangers  and  Precautions.  89 

It  should  be  a  universal  rule  never  to  look 
into  an  opening  in  a  gas  motor  without  first 
holding  a  flame  in  front  of  the  opening  for  a 
certain  time,  keeping  meanwhile  at  a  safe  dis- 
tance. 

In  the  case  of  the  ignition  valve  most 
commonly  used  it  is  conceivable  that  with 
large  motors  the  person  who  is  starting 
the  motor  failing  to  overcome  the  com- 
pression, and  holding  on  to  the  wheel, 
may  be  thrown  over  the  engine.  Such 
ignition  apparatus  operates  not  only  at  the 
dead  point,  but  also  during  the  compres- 
sion period  about  the  middle  of  the  stroke 
in  case  the  motor  goes  backward. 

As  with  other  machines,  so  with  gas 
engines  it  is  a  very  proper  precaution 
never  to  touch  anything  in  motion,  and  to 
reserve  the  cleaning  and  wiping  off  of  the 
engine  until  it  stops.  Moreover,  the  fixed 
parts  of  a  motor  should  be  disturbed  as 
little  as  possible  while  running. 

A  nut  should  never  be  tightened  up  or 
loosened  while  the  motor  is  running  ;  even 


90  Dangers  and  Precautions. 

if  one  is  apparently  entirely  out  of  reach 
of  the  moving  parts,  the  spanner  may  slip 
and  the  body  be  thrown  within  the  range 
of  danger.  The  warning  to  let  alone  the 
connecting-rod  cannot  be  too  emphatically 
stated. 

If  the  rod  is  tightened  up  too  much  it 
will  grind  on  the  crank-pin,  and  serious 
cutting  is  inevitable. 

The  fly-wheel  ought  to  be  surrounded 
with  a  rail  one  side  of  which  is  removable. 
The  crank,  the  governor,  and  all  gearing 
should  be  protected  with  suitable  coverings. 

A  bad  practice  which  is  very  general  in 
starting  small  motors  is  that  of  throwing 
off  the  belt,  and  later,  when  the  motor  is 
set  in  operation,  to  put  the  belt  on  again 
by  hand.  Even  the  most  experienced  may 
slip  and  the  hand  may  be  caught  between 
the  belt  and  the  pulley,  or  even  by  the 
arms  of  the  fly-wheel  ;  where  the  belt  pul- 
ley is  as  high  as  the  head  the  danger  is 
particularly  serious  of  having  the  belt 
thrown  off  sideways  and  striking  the  face. 


CHAPTER  VI. 

OIL   ENGINES. 

THE  use  of  the  gas  engine  requires  that 
a  supply  of  gas  should  be  at  hand,  and  it  is 
therefore  unavailable  in  country  houses  or 
villages  where  gas  is  not  to  be  obtained. 
In  such  cases  it  becomes  necessary  to 
manufacture  the  gas  one's  self.  For  a  very 
large  engine,  say  100  Horse  Power  or 
above,  it  pays  to  put  up  a  gas  making 
plant  which  resembles  in  its  essential  de- 
tails the  modern  apparatus  for  making 
water  gas.  The  process,  however,  is  a 
continuous  one,  and  the  result  is  a  much 
poorer  (or  more  dilute)  gas,  which  has  re- 
ceived the  name  of  "  producer  gas." 

For  use  in  a  gas  engine,  however,  this 
dilution  is  not  a  disadvantage,  since  illumi- 
nating gas  has  to  be  diluted  in  this  case. 


92  Oil  Engines. 

When  producer  gas  is  used,  about  four 
times  the  quantity,  as  compared  with  or- 
dinary gas,  is  taken  for  each  charge  of  the 
cylinder,  and  proportionally  less  air.  The 
mixture  when  made  has,  however,  about 
the  same  calorific  power  per  cubic  foot  as 
the  ordinary  explosive  mixture.  It  can  be 
used,  therefore,  in  the  ordinary  gas  engine 
to  .produce  the  same  effect,  but  a  some- 
what higher  degree  of  compression  is  ad- 
visable, and  electric  ignition  is  found,  in 
this  case,  to  be  more  certain  than  tube 
ignition. 

For  moderate  sized  engines  some  sim- 
pler means  of  producing  the  gas  must  be 
found.  Hence  the  gasolene  and  oil  en- 
gines, which  are  essentially  gas  engines, 
for  which  the  gas  is  produced  on  the  spot, 
and  used  as  fast  as  produced.  In  some 
forms  of  these  engines  no  gas  is  produced 
anywhere  outside  of  the  engine  cylinder. 
When  the  volatile  products,  such  as  naph- 
tha and  gasoline,  are  used,  it  is  sufficient 
either  to  draw  air  through  the  liquid  or  to 


Oil  Engines. 


93 


inject  a  small  portion  of  it  at  each  alternate 
revolution  into  the  warm  cylinder.  The 
very  facility  with  which  naphtha  and  gaso- 
lene volatilize  is  a  source  of  danger,  and 
the  use  of  the  oil  engine  proper,  which 
uses  a  safe  heavy  oil  flashing  at  150°  to 
300°,  is  rapidly  growing  in  favor. 


FIG.  12. 

To  this  class  of  engines  the  "  Hornsby- 
Akroyd"  oil  engine  stands  in  about  the 
same  relation  as  the  "  Otto"  does  to  gas 
engines,  or  rather  did  before  the  "  Otto" 
patents  expired.  This  engine  is  charac- 
terized by  extreme  simplicity,  which  ren- 
ders it  more  easy  to  handle  than  a  gas  en- 
gine, and  allows  of  its  being  left  to  itself 
for  much  longer  periods.  The  most  strik- 


94 


Oil  Engines. 


ing  peculiarity  ot  the  "  Hornsby-Akroyd" 
oil  engine  is  the  total  absence  of  ignition 
apparatus.  The  manner  in  which  the  au- 
tomatic ignition  is  effected  will  be  easily 
understood  from  figs.  12,  13,  and  14. 

The  first  of  these  represents  the  period 
of  suction  during  which  air  only  is  drawn 
into  the  cylinder,  and  oil  is  at  the  time  in- 


FIG.  13. 

jected  into  the  chamber  forming  an  exten- 
sion of  the  cylinder  and  connected  with 
the  same  by  a  narrow  neck.  This  exten- 
sion to  the  cylinder  is  the  combustion 
chamber,  and  is  not  water  jacketed,  so 
that  it  remains  at  a  temperature  approxi- 
mating a  dull  red.  The  oil  is  forced 
into  it  in  a  thin  stream  by  a  pump  actu- 


Oil  Engines. 


95 


ated  by  the  same  lever  that  opens  the  air 
valve. 

At   the   end   of   this  first  operation  we 
have  : 

(a)  The  cylinder  full  of  pure  air. 

(b)  The  combustion  chamber  full  of  oil 
vapor. 

Neither  of  these  alone  is  explosive,  but 


FIG.  14. 

on  the  return  stroke  of  the  piston,  repre- 
sented by  fig.  13,  the  air  is  forced  through 
the  narrow  neck  into  the  combustion  cham- 
ber, forming  there  a  mixture  of  vapor  and 
air,  which,  at  the  completion  of  the  stroke, 
ignites.  We  now  have  the  third  period  in 
which  the  expanded  air  drives  out  the  pis- 
ton, as  seen  in  fig.  14.  The  fourth  period, 


96  Oil  Engines. 

not  shown,  is  that  during  which  the  prod- 
ucts of  combustion  are  swept  out  of  the 
cylinder  by  the  return  stroke  of  the  piston. 

Before  starting  the  engine  the  combus- 
tion chamber  or  "  vaporizer"  must  be 
heated  ;  this  may  be  done  by  a  "  Bunsen" 
burner  where  gas  is  obtainable,  but  an  oil 
lamp  is  supplied  for  use  where  this  is  not 
the  case.  The  lamp  is  placed  on  a  bracket 
immediately  below  the  vaporizer,  and  the 
flame  is  blown  up  with  a  little  fan  driven 
by  hand,  all  of  which  are  clearly  seen  in 
the  cut  of  this  engine  forming  the  frontis- 
piece. The  vaporizer  is  protected  from 
air  currents  by  a  hood  which  is  remova- 
ble, and  which  itself  has  a  small  cover 
forming  a  damper. 

The  regulation  is  effected  not  by  the  hit 
and  miss  principle,  but  by  allowing  more 
or  less  of  the  oil  to  flow  back  to  the  oil 
reservoir,  usually  in  the  base  plate  of  the 
engine.  This  is  effected  by  a  sensitive 
governor,  which  opens  a  by-pass  in  the 
valve  box  attached  to  the  vaporizer,  when 


Oil  Engines.  97 

the  speed  momentarily  increases.  If  the 
engine  is  to  be  run  continuously  at  less 
than  full  power,  the  stroke  of  the  oil  pump 
can  be  readily  adjusted  to  the  work  re- 
quired of  the  engine,  and  less  work  will 
be  thrown  upon  the  governor. 

To  START  THE  ENGINE. 

(a)  Fill  and  light  the  lamp. 

(&)  Oil  engine  all  round,  fill  up  oil  cups. 

(c)  Blow  up  lamp,  gently  at  first,   then 
briskly,    until  the   lamp   goes   out,    when 
the  vaporizer  should  be  hot  enough. 

(d)  Throw  out  compression  by  turning 
lever  to  position  marked  "  To  start." 

(e)  Try  oil  pump. 

(/)  Turn  over  fly-wheel  till  explosion 
takes  place. 

(g)  Turn  back  starting  lever  to  position 
marked  "  To  work." 

(h)  Throw  on  belt. 

REMARKS  ABOUT  STARTING. 
In  this  order  of  procedure  the  lamp  is 


98  Oil  Engines. 

lighted  before  oiling  the  engine,  in  order 
to  give  it  time  to  warm  up.  In  turning 
over  the  fly-wheel  there  is  a  certain  knack, 
which  is  easily  acquired,  and  renders  the 
starting  up  of  even  large-sized  engines 
tolerably  easy.  The  wheel  may  be  turned 
backward,  and  the  compression  will  often 
cause  an  explosion  and  start  the  engine  ;  if 
not,  the  rebound  thus  obtained  from  the 
compressed  air  will  assist  in  turning  the 
fly-wheel  in  the  forward  direction. 

If  the  engine  starts  up  in  the  wrong 
direction  it  will  generally  reverse  itself 
after  a  few  turns,  and  at  the  moment  of 
reversal  it  may  be  helped  along  by  hand. 
After  a  few  trials  the  attendant  will  find 
that  very  little  actual  work  is  required. 
If  he  prefers  to  simply  turn  the  fly-wheel 
in  the  forward  direction,  he  will  find  by 
trial  that  a  certain  one  of  the  spokes  is 
more  favorable  to  his  effort  than  the  others. 
It  is  the  one  which  he  reaches  by  stooping 
down  to  effect  the  compression.  This 
should  be  laid  hold  of  and  followed  around. 


Oil  Engines.  99 

To  STOP  THE  ENGINE. 

Turn  over  the  crutch-handled  regulator 
on  the  governor  bracket  to  position  marked 
"Shut."  To  stop  quickly,  hold  down 
the  air  valve  lever  at  the  same  time.  If 
the  engine  does  not  stop  readily  the 
spring  of  the  horizontal  check  valve  of  the 
vaporizer  valve  box  is  too  weak,  or  is 
broken,  and  part  of  the  oil  enters  the 
vaporizer  instead  of  all  coming  through 
the  overflow  valve,  as  it  should  do  when 
the  handle  is  turned  to  "  Shut." 

FAILURE  TO  START. 

In  nine  cases  out  of  ten  this  is  due  to 
either  not  having  heated  the  vaporizer  hot 
enough  or  to  having  left  it  time  to  cool 
off  before  starting.  See  that  the  lamp  is 
in  good  order,  refill  it  and  heat  up  again. 
If  the  engine  still  fails  to  start,  make  exami- 
nation of  its  condition  in  the  order  given 
below  until  the  source  of  trouble  is  found, 
then  start  again.  But  first  of  all  see  that 
the  oil  reservoir  is  not  empty. 


ioo  Oil  Engines. 

EXAMINATION  OF  ENGINE  IN  DETAIL. 
Oil  Pump. 

(a)  Turn  over  crutch-handled  regulator 
on  governor  bracket  to  position  marked 
"  Shut,"  when  all  the  oil  will  pass  through 
the  by-pass  valve,  and  work  the  pump  by 
hand.     If  a  full  stream  of  oil,  free  from  air 
bubbles,  is  thrown  out,  the  pump  is  prob- 
ably all  right  ;  and  this  test  should  always 
be  applied  at  the  time  of  starting.     If  the 
oil  pump  does  not  work  satisfactorily,  pro- 
ceed as  follows  : 

(b)  Open  the  three-way  cock  on  oil  res- 
ervoir ;  if  oil  flows  out  freely  the  filter  is 
all  right ;  if  not,  take  it  out,  clean,  or  renew 
it.     If,  after  fixing  the  filter,  the  pump  is 
still  unsatisfactory,  test  it  for  air  as  fol- 
lows : 

(c)  Disconnect  oil  delivery  by  the  union 
attached  to  vaporizer  valve   box  ;    pump 
up  oil  till  it  overflows,  then  press  thumb 
over  outlet  and  try  the  pump  with  sudden 
jerk.     If  the  plunger  yields  and  yet  no  oil 


Oil  Engines.  101 

escapes  past  the  thumb,  air  is  in  the  pipes. 
This  fact  may  be  further  proved  by  mak- 
ing several  sharp  strokes  with  the  pump, 
when,  on  releasing  the  thumb  suddenly, 
the  oil  will  be  projected  a  considerable 
distance  above  the  pipe  by  the  elastic  force 
oi  the  air  contained  within  the  pipe. 

If  no  air  is  found  in  the  pipes,  examine 
action  of  valves. 

(d)  Give  the  pump  a  steady  pressure 
while  the  thumb  is  held  on  the  outlet.  If 
the  plunger  yields  under  this  steady  press- 
ure, but  not  under  a  sudden  jerk,  then  the 
suction  valves  are  not  tight.  If  after  care- 
fully washing  out  the  pump  and  valve 
boxes  with  oil,  the  fault  is  not  remedied, 
tap  the  steel  ball  valves  slightly  on  their 
seat  with  a  copper  punch. 

(NOTE. — The  pump  being  provided  with 
two  valves  in  series,  both  for  suction  and 
delivery,  of  which  the  steel  balls  are 
critically  examined  before  putting  in,  de- 
rangement of  the  pump  is  of  rare  occur- 
rence.) 


IO2  Oil  Engines. 

VAPORIZER  VALVE  Box. 

In  this  box  there  are  two  valves.  The 
vertical  one  is  regulated  by  the  governor, 
and  when  the  engine  runs  faster  than  its 
proper  speed,  the  governor  pushes  it 
down,  thus  opening  it  and  allowing  some 
oil  to  overflow  into  the  little  conical  dish 
for  catching  it.  The  horizontal  valve  in 
this  box  is  a  back-pressure  valve,  and  if  at 
any  time  this  valve  should  not  be  working 
properly,  vapor  would  be  seen  coming 
out  of  the  overflow  pipe,  and  in  that  case 
the  valve  should  be  looked  to.  By  screw- 
ing off  the  outside  cap,  the  tail  of  this  valve 
can  be  seen,  and  if  the  valve  is  turned 
round  a  few  times,  it  will  probably  dis- 
lodge any  dirt  that  may  have  got  under  it ; 
if,  however,  this  does  not  stop  it  leaking, 
then  the  valve  had  better  be  taken  out  for 
inspection. 

(NOTE. — In  all  cases  where  packing  is  re- 
moved from  joints,  renew  it  with  packing  of 
exactly  the  same  thickness.} 


Oil  Engines.  103 

To  test  the  vaporizer  valve  box,  take  it 
off  and  connect  it  up  to  its  oil  supply  pipe 
from  the  pump,  so  that  the  jet  out  of  its 
spraying  hole  or  holes  can  be  directed  in 
any  convenient  direction  where  it  can  be 
seen.  Now  stroke  the  pump  at  as  near 
the  actual  working  speed  as  possible.  The 
jet  or  jets  produced  should  be  clear,  with 
distinct  and  abrupt  pauses  between  each 
delivery,  as,  if  oil  dribbles  into  the  vapor- 
izer on  the  working  and  exhaust  strokes 
of  the  engine  when  it  is  not  wanted,  a 
waste  occurs.  This  condition  is  very  essen- 
tial for  economical  working. 

With  ordinary  care  the  oil  engine  is  sub- 
ject to  very  little  derangement,  and  if 
trouble  occurs  it  can  very  readily  be  lo- 
cated and  corrected  by  proceeding  in  a 
svstematic  manner. 


THE  OTTO  GAS  ENGINE. 

Working  without  Boiler,  Steam,  Coal,  Ashes  or -Attendance. 

OVER    45,000   SOLD. 


Started  Instantly  it  gives  Full  Po^er  Immediately. 
When  Stopped  All  Expense  Ceases. 

FOR  COAL  GAS,  GASOLINE,  NATURAL  GAS, 
PRODUCER  GAS. 

THE  OTTO  GAS  ENGINE  WORKS, 

(Incorporated. ) 

33d   and  Walnut   Streets, 

BRANCH  OFFICE  :  PHILADELPHIA,    PA, 

245  Lake  St.,  Chicago,  III. 


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The  flanufacture  of  Soap  and  Candles,  Lubri- 
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Second  edition  revised  by  Henry  Leask. 
446  pages,  104  illustrations,  I2mo,  cloth 4.00$ 

An  Elementary  Text=book  on  Steam  Engines 
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THE  BEST  BOOK  ON  ICE  MAKING. 

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The  Management  of  Gas  and  Oil  Engines, 
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Higgs,  W.  P.— Algebra  Self  Taught.  A  valuable  aid 
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Hornby,  J. — The  Gas  Engineer's  Laboratory  Handbook. 
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Ornamental  Penmans  Pocket  Book  of  Alphabets,  for 
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Rowell,  H. — Manual  of  Instruction  in  Hard  Soldering. 
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Watson,  E.  P., — How  to  Run  Engines  and  Boilers.  Prac- 
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